When to replace serpentine belt tensioner? (The answer is found)

When to Replace Your Belt Tensioner You should expect to replace your belt tensioner in the 40,000-70,000 mile range. It is also customary to swap more than one part simultaneously, usually a worn-out pulley from other systems and even the serpentine belt itself.

What are the signs of a bad belt tensioner?

  • The most common symptom of a bad or failing drive belt tensioner is noise from the belts or tensioner. If the tensioner is loose the belts may squeak or squeal, especially when the engine is first started. It is also possible for the tensioner pulley or bearing to wear out, in which case the vehicle will produce a grinding noise from the pulley.

How do you know if your serpentine belt tensioner is bad?

The symptoms of a loose serpentine belt include a loud squealing noise when the engine is started or when the steering is turned all the way to one side. A serpentine belt that keeps slipping off the pulley is another symptom of a bad tensioner.

How long should a serpentine belt tensioner last?

Most modern cars that roll off the dealer’s lot as a new vehicle will have a 60,000 to 100,000-mile life expectancy for the serpentine belt, tensioners, and idler pulleys.

What happens when a belt tensioner goes bad?

Many of the engine’s accessories, such as the alternator, water pump, and AC compressor, can be belt driven. A seized or loose drive belt tensioner can cause the belt to snap, which will disables those accessories and can cause problems such as overheating, a dead electrical system and battery, or a disabled AC system.

Is idler pulley same as tensioner?

The primary distinction between tensioners and idler pulleys is the presence of an adjustable bolt. Tensioners are positioned on the bolt through mounting. Idler pulleys are not mounted to an adjustable bolt. However, if bearings fail, tensioner and idler pulleys both require replacement.

When should I replace my car tensioner?

When to Replace Your Belt Tensioner You should expect to replace your belt tensioner in the 40,000-70,000 mile range. It is also customary to swap more than one part simultaneously, usually a worn-out pulley from other systems and even the serpentine belt itself.

Do belt tensioners wear out?

Tensioners And Belts Do Wear Out Because, the tensioner drives the belt, wear on both will happen at some point. So, having either one fail could cause a multitude of problems.

How much does it cost to get a belt tensioner replaced?

To get the belt tensioner replaced, you will pay anywhere from $140 to almost $400. The price of parts and labor varies from one car to the next, with most labor costs coming in at about $70 or $80.

How do I know if I need a new belt tensioner?

Appearance: Cycle the tensioner (mounted on the engine) through the entire range of motion (from stop to stop) by applying torque to the arm with a wrench. The tensioner arm should move smoothly and freely. Solution: If you notice a binding, sticking or grinding tensioner arm, the tensioner should be replaced.

What are the symptoms of a bad idler pulley?

Signs and Symptoms of a Bad Idler Pulley

  • Chattering, Squealing, or Chirping Sound.
  • Corroded Surface.
  • Excessively Loose Idler Pulley.
  • A Bad Idler Pulley May Spin Excessively.
  • Slow to No Spin or Binding.

When should I replace idler pulley?

An idler pulley is expected to wear over time, and eventually the pulley will fail. Replacement intervals for idler pulleys vary, but are usually within the 50,000 to 100,000 mile range. Replacement often coincides with expected serpentine/accessory belt replacement periods.

Diagnosing & Replacing a Serpentine Belt Tensioner

V-belts were used to power one or two accessories on older automobiles. Your car may have had anywhere from one to four V-belts, depending on the extras it was equipped with. In modern automobiles, every accessory is controlled by a single lengthy belt. Serpentine drive belts are what these belts are referred to as. It is not necessary to change the tensioning screw in a bracket when using a spring-loaded tensioner for the serpentine belt. Instead, the tensioner is spring-loaded. Most likely, you’ll be replacing the serpentine belt at least once before you’ll need to repair the tensioner on your vehicle.

However, every time you change the belt, you should inspect the tensioner for wear and tear.

Symptoms of a Broken Tensioner

The tensioner is positioned on the outside of a serpentine belt, on the smooth side of the belt, and it is responsible for keeping the belt taut. It applies strain to the belt in order to hold it in place. As the serpentine belt expands over time, the tensioner increases the amount of stress applied to it in order to maintain it tight. A damaged tensioner may make a clicking or squealing sound. A belt might also be broken, and if the belt becomes entangled in one of the pulleys, you would hear the belt slamming against the pulley.

  • The battery will not charge, and the battery light will illuminate. After a while, the automobile begins to overheat
  • You will lose control of the steering wheel. The air conditioner is not functioning properly

Checking the Tensioner

Every time you change the serpentine belt, make sure the tensioner is working properly. Check to check if the pulley spins freely by spinning it. If you hear grinding or if the pulley does not spin freely, the tensioner should be replaced. Whenever you replace the belt, it should need a significant amount of muscular strength to move the tensioner. If you are able to move it with ease, the spring tension is most likely insufficiently tight. Belt tension can also be used to verify the tensioner’s performance.

If you are experiencing intermittent issues such as power steering skipping, a vehicle that isn’t constantly charged, or air conditioning that isn’t functioning properly, you should check the tensioner.

Tensioner Problems

When a serpentine belt tensioner is used for a long period of time, it might wear out or develop other issues. When inspecting the tensioner, keep an eye out for the following things.

  • Inspect the tensioner housing for signs of rust. Rust will ultimately cause the tensioner to freeze
  • However, this is unlikely. Remove any debris or mud that has accumulated in the tensioner
  • Bad bushings produce noise (often grinding noises), but they can also cause the belt to vibrate as well. If the pivot arm is loose, it has the potential to cause the belt track to be incorrect, resulting in the belt being destroyed. If the spring is weak, it will not be able to exert sufficient strain on the belt. If the tensioner housing has fractures or other damage, it has the potential to break the belt and cause other elements in front of it, such as the radiator, to malfunction.

Replacing the Tensioner

It is recommended that you photograph the belt routing diagram before removing it from your car or draw a drawing of the routing plan before removing it. Loosen the tension on the belt with the use of a tensioner release tool. It may be possible to leave the belt on the majority of the other pulleys if you are not changing it.

Remove the bolts that hold the tensioner to the block in place. Remove the tensioner from the system. Replace the old tensioner with the new one and reattach the belt to the tensioner’s mounting bracket.

Serpentine belt, tensioner: problems, signs of wear, when to replace, noises

The most recent update was on November 17, 2018. Belt with serpentine grooves. In a modern automobile with a gasoline or diesel engine, you will find at least one serpentine belt if you open the hood and look underneath. Take a look at this snapshot. Cars with two or three belts are available; electrified vehicles do not have belts. This belt is responsible for driving accessories placed on your engine, such as an alternator, water pump, and compressor for your air conditioner. A serpentine belt differs from an atiming belt in that it has a serpentine pattern.

It is possible to examine the serpentine belt from below the hood, which is positioned on one of the engine’s sides.

What might cause a belt to squeak in the first place?

What is the price range?

What happens if a serpentine belt breaks?

The serpentine belt has broken. If a serpentine belt fails, a vehicle will not be able to be driven and will need to be towed. If the engine is operated without the use of a serpentine belt, it is possible that the engine would overheat due to the lack of operation of the water pump. A damaged belt might potentially cause harm to other sections of the vehicle. We’ve seen radiator shrouds that have been cracked and coolant hoses that have been shredded as a result of a ruptured belt. If you have a broken serpentine belt, you’ll hear loud clanking or knocking sounds coming from under the hood as well as other signs of a broken serpentine belt.

When a vehicle is equipped with a hydraulic power steering pump, the steering becomes stiff.

Commonbelt and tensioner problems that can cause abelt to break or produce noises

Here are a few examples of frequent issues: A glazed serpentine belt vs a fresh serpentine belt. Wear and tear on a regular basis. On the ribbed side of a new serpentine belt, a soft felt-like surface has been added. If you scroll down to the bottom of the page, you will find a photo of a broken belt. As the belt wears down, the rubber hardens and cracks. A belt that has seen better days stretches and loses tension. It is as a result of this that the belt starts slipping from time to time. Squealing or chirping noises emanating from under the hood may be heard when the engine is started first thing in the morning or in rainy weather, and it is caused by corrosion.

  • If there are no other issues and the belt tensioner is in excellent working order, a new serpentine belt should be sufficient to resolve the issue.
  • When there is an oil leak, a serpentine belt might be damaged in a short amount of time.
  • In some cases, an engine develops oil leaks around the belt region, resulting in the belt becoming drenched in oil (as shown in the photograph).
  • It has been our experience that a new serpentine belt will survive less than a week in an engine that leaks oil around the belt location.
  • First and foremost, oil leaks must be repaired.
  • If the leak is coming from a camshaft seal or another source, the repair will be more involved.
  • An automated spring-loaded belt tensioner might become seized inside or wear out on its shaft if it is not maintained properly.

Any belt must be tensioned properly in order to function properly.

A serpentine belt will begin to slip if the tension is not properly maintained.

We’ve seen seized belt tensioners cause a loose serpentine belt to slide off the tensioner, and we’ve seen them fail completely.

Another indicator of a malfunctioning tensioner is a serpentine belt that keeps falling off the pulley while driving.

It costs $20-$50 to purchase a spring-loaded automated belt tensioner, plus $75-$170 to have it installed by a professional.

4.There are issues with the hydraulic belt tensioner.

It, too, has the potential to collapse.

Many automobiles, including the Toyota Corolla, Matrix, BMW, and Mazda, suffer from this failure on a regular basis.

Otherwise, unless the belt appears to be in like-new condition, it should be changed as well.

The cost of labor to replace it ranges from $75 to $170.

5.The manual belt tension is not properly adjusted.

Another illustration is the belt tension adjustment in a Toyota Yaris.

When an older Japanese or Korean automobile is started, it creates a loud screeching noise that you have undoubtedly heard before.

If the belt is faulty, it must be changed and carefully tightened to ensure appropriate operation.

As a result, the belt began to scream and wear more quickly.

A serpentine belt is a type of belt that operates on many pulleys.

This problem is frequently detected after a recently replaced belt continues to scream or wears out quickly.

When one of the pulleys is out of alignment, you can usually tell by looking at it.

The belt is now squeaking.

As a result, the alternator pulley was misaligned with the belt, causing the belt to scream and wear out more quickly.

In this particular instance, the belt and worn-out alternator nuts were replaced in order to realign the alternator.

7.An idler pulley or tensioner bearing that is noisy.

It is referred to as an idler pulley.

A whining/whirring or screaming noise might be heard when that bearing wears out or becomes damaged.

A specialized stethoscope is used by mechanics to locate the source of the noise in the engine compartment.

It is possible that a mechanic will have to remove a belt and inspect each of the gadgets that are powered by the belt one by one.

The type of repair required will be determined by whatever component is damaged. The idler itself is not very expensive: $15-$35 for the part + $60-$170 for labor if it is just a simple repair. The cost of replacing an air conditioning compressor or alternator might range from $450 to $850.

When a serpentine belt needs to be replaced

This serpentine belt is still in good condition, and it is not necessary to replace it at this time. A serpentine belt may last anywhere between 30,000 and more than 100,000 kilometers. Most automobile manufacturers do not specify the periods between serpentine belt replacements, but rather urge that the belt be inspected during routine maintenance. The following is what Toyota advises for the serpentine belt in the 2017 Toyota Camry, as an illustration: At 60,000 miles/72 months, the vehicle receives its first inspection.

Cracks have been discovered in this serpentine belt, and it will need to be replaced.

It is usually obvious when a belt has reached the end of its useful life.

An oil-saturated or stretched serpentine belt must also be changed when it is discovered to be defective.

Serpentine belt replacement cost

If your vehicle has two belts, we recommend that you replace them both at the same time in order to save money on labor costs. It’s also a good idea to get an old serpentine belt replaced before embarking on a lengthy road journey. Continue reading:Car checklist before a lengthy road trip. The cost of a serpentinebelt replacement ranges from $18 to $75 for the part and $50 to $150 for labor.

How easy is it to replace a serpentine belt DIY?

The serpentine belt replacement may be rated anywhere from 3 to 7 on a scale of 1 to 10 (leave it to the experts), depending on the automobile. The belt diagram that displays the routing of a serpentine belt will be required in order to replace it. The owner’s manual for certain automobiles contains information on how to navigate the vehicle. Another option is to sketch up a routing plan before removing the old belt from the machine. When it comes to front-wheel drive automobiles with a transversely placed engine, there is little space between the engine and the frame, making replacing the serpentine belt a difficult task.

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If you want to order a serpentine belt, you may need to know your vehicle’s VIN number because the belt may be different for different years and engines.

If you want correct repair instructions, we have included numerous links at the bottom of this page, via which you may obtain a subscription-based access to a factory service manual for a reasonable fee.

Your Car’s Serpentine Belt

Although it will not keep your pants up, it will carry electricity to your vehicle’s critical components.

When you look at a serpentine belt, you see one long snaking, winding belt. It is this belt that maintains your alternator functioning smoothly and effectively, as well as your power steering pump, air conditioning, and—in certain cases—your water pump.

Didn’t cars used to have more than one belt?

Back in the day, many different components of an automobile were connected by separate belts. However, even though each belt could be replaced separately, these vehicles faced variable or degraded performance when individual belts began to wear down and eventually failed. Now when automobiles are equipped with a single belt — the serpentine belt — this is no longer a consideration. It is, nevertheless, vital that frequent checks are performed to ensure that the belt is in excellent working order.

How often does a serpentine belt need to be replaced?

As a result of developments in rubber technology, serpentine belts are engineered to endure a long time—much longer than in the past. Under ideal conditions, a belt should be able to accompany you for an average of 60,000 to 100,000 kilometers. It’s rather impressive. Some belts, on the other hand, are manually tensioned and may require readjusting. Others feature a self-tensioning system that might wear out over time and may need to be maintained or replaced. Something to keep in mind: in the majority of situations, if the belt breaks, the car will come to a complete stop.

Make a scheduled appointment.

How many belts do most vehicles have?

Today, there is a single belt that drives them all, or at least the vast majority of them. It is referred to as the serpentine belt. Some rides may have an extra belt to drive specific accessories, but the serpentine is responsible for the majority of the labor. Vehicles were formerly supplied with a variety of belts to power various parts and components until an all-in-one serpentine solution was developed. Inspection and/or replacement of your engine belt are highly recommended. Make a scheduled appointment.

What happens as a belt gets older?

They can get worn, frayed, cracked, or glossy or ‘glazed,’ and rubber pieces can break loose and fall off the belt. An old belt may also begin sliding or squeaking, get polluted with fluid, or become misaligned, all of which need the replacement of the belt in question. The driving torque to all of the engine’s accessories is lost if the belt becomes worn or damaged. An old belt may even crack, leaving you stranded. Make an appointment for an engine belt inspection at your nearest Firestone Complete Auto Care.

What is the benefit of having a belt replaced?

Driving on a worn-out belt is a recipe for disaster because it provides power to nearly all of an engine’s accessory components. That means that when your belt breaks, slides, and eventually wears out, everything in your vehicle stops operating, from the power steering pump to the alternator and air conditioner. Furthermore, the parts that it regulates might suffer serious harm as a result of the malfunction. Broken hoses and belts are inconvenient; a broken engine is far more inconvenient. You may reduce the likelihood of a breakdown by replacing your belt on a regular basis.

Make time to have your belt inspected.

Your belt’s present condition may be determined by doing either an annual automobile inspection or a visual check when getting an oil change.

This will give you a decent indication of when your belt should be replaced. Drive with complete confidence. Check the condition of your belt. Make a scheduled appointment.

What is a “belt tensioner,” and what is the benefit of replacing it when a belt is replaced?

Many modern automobiles are fitted with an automated belt tensioner, which is a self-tensioning system that keeps the belt taut. Designed to maintain a specified level of tension on the serpentine belt, these tensioners ensure that the belt performs correctly and that your vehicle remains on the road. Your serpentine belt is similar to a massive rubber band that is rotating at breakneck speed. In addition, it must maintain a balance between flexibility and tension, much like a rubber band. The majority of tensioners are equipped with an internal spring and pulley that delivers the necessary force to the serpentine belt to keep it taut and in place.

  1. The worst-case situation is that a slack belt will fall loose from its pulleys.
  2. The following is a quick fact: If your serpentine belt is loose, you may be experiencing additional mechanical issues, such as a poorly running water pump, which can cause the engine to overheat.
  3. It is important that you bring your vehicle in as soon as possible.
  4. Do you need to get your serpentine belt inspected?

How many different types of belts are there?

A serpentine belt is the most prevalent type of belt used in modern automobiles, and it is responsible for the operation of nearly every system in your vehicle. Alternately, your vehicle may be equipped with a succession of V-belts (sometimes known as fan belts), which are designed to serve the same general-purpose duties as a serpentine belt. Some vehicles may also have a ‘toothed’ timing belt in the engine, which is critical to the overall operation of the vehicle’s engine. This belt may be used to drive the water and oil pumps, among other important components.

What are symptoms my vehicle’s belt may require a belt replacement?

  • Chirp or squeal: When a belt begins to slide, a squealing sound may be heard. This is caused by the belt slipping. If the belt and pulley are not operating correctly, low belt tension, or belt strain and/or wear are the causes of this problem. Belt slippage can be exacerbated by leaks of oil or antifreeze, among other things. It is critical that you have your vehicle examined as soon as possible in order to prevent more issues from occurring. And with this sound, they will finally succeed. Performance degradation of the system: Perhaps your power steering has failed, your battery has unexpectedly depleted, or your engine has simply stopped working. A properly working serpentine or V-belt is in charge of all of these functions. Once your belt has been compromised, it may cause more harm to the key systems that rely on it, such as the alternator, water pump, power steering, and air conditioning, as well as the rest of your vehicle. Unfortunately, the subsequent damage can be substantial, and there is little notice prior to the occurrence
  • As a result, there is little time to prepare. The check engine light is illuminated as follows: The fact that this is happening might be an indicator that something is amiss with the belt.

It is possible that funny noises are caused by difficulties with other parts. Never turn a blind eye to a commotion. Where there is noise, there is the possibility of a problem. Maintain the safety of your vehicle and the protection of your four-wheel investment. Don’t disregard the warning signs of a failing belt. Make an appointment to have an inspection performed.

Does Firestone Complete Auto Care install belts that meet my vehicle’s specifications?

Yes, we do have one. The belts we install are made by Bando and Dayco, who are well-known among automotive specialists and original equipment manufacturers as pioneers in automotive parts technology and innovation. Advanced rubber compounds are used in the design of each Bando and Dayco belt we install, resulting in increased longevity and greater wear prevention. In the case that your vehicle requires a different brand of belt, we may also install belts from other manufacturers as specified by the vehicle’s manufacturer.

Make a scheduled appointment.

Tech Tip: Inspect the Spring-Loaded Automatic Belt Tensioner when Replacing Serpentine Belt

Technical Editor Larry Carley contributed to this article. More information is available by clicking here. Serpentine belt drives are used to drive the engine-driven accessories on the majority of late-model engines. And the majority of people are aware that belts are a maintenance item that must be replaced at some point. Many people are unaware that the spring-loaded automatic tensioner that keeps a serpentine belt taut is also a wear item, as well as a wear item. As a result, when it comes time to replace the belt, it is possible that the automatic tensioner will also need to be replaced.

  1. The tensioner also gives a little “give” so it can absorb and cushion shock loads on the belt that occur when the A/C compressor clutch cycles on and off.
  2. But nothing lasts forever, not belts and nor automated tensioners.
  3. The belt may become cracked, glazed, and loud as it approaches the end of its service life.
  4. When the water pump stops working, the flow of coolant ceases and the engine begins to overheat.
  5. When the power steering pump stops turning, the steering suddenly gets very stiff and hard to control.
  6. But the automatic tensioner is not inspected to make sure it is still working properly and is in good condition.
  7. Belt tension is critical.

Slippage also causes the belt to run hot and age prematurely.

Too much tension on a belt may overload it as well as the shaft bearings on the water pump, alternator, power steering pump and air conditioning compressor, possibly leading to premature failures in these components.

These early units were fixed tensioners that required manual adjustment.

The spring-loaded design eliminated the need for manual adjustments and assured proper belt tension for the life of the belt.

Even so, the tensioner should always be inspected when changing a belt because: Rust or corrosion can jam the tensioner housing and prevent it from rotating freely.

Corrosion is usually a result of road splash, especially in areas where roads are heavily salted during the winter.

A loose or worn pivot arm can allow unwanted movement that results in belt noise and misalignment.

A worn bushing in the tensioner pulley can cause vibrations and noise.

A weak or broken spring inside the tensioner can’t maintain proper tension and the belt will slip.

Cracks or damage to the tensioner housing or pulley arm may prevent it from rotating smoothly and maintaining proper belt tension.

Belt glazing (caused by slipping) (caused by slipping).

This means the spring inside the tensioner is weak and/or the bushing is worn.

Wobble in the tensioner pulley (or idler pulley) (or idler pulley).

Belt or tensioner noise.

Any squealing, rumbling, growling or chirping noises should be investigated to determine the cause.

The probe should be placed against the bolt in the center of the tensioner pulley wheel to listen for bearing noise.

The same goes for all the engine-driven accessories (water pump, alternator, PS pump and A/C compressor).

Physical damage of any kind on the automatic tensioner pulley may indicate excessive tension or physical interference.

If an idler pulley is damaged, inspect the tensioner also because vibrations caused by a bad idler pulley may damage the tensioner.

Use a socket with a long handle ratchet or breaker bar on the tensioner pulley center bolt to rotate the tensioner.

If it fails to move at all, the tensioner is jammed and needs to be replaced.

The arm should not wobble or twist.

Also note the position of the arm on the automatic tensioner.

If the position of the arm is outside these marks, it indicates a problem (the belt may be too long or too short, or the tensioner may be jammed) (the belt may be too long or too short, or the tensioner may be jammed).

Misalignment and bearing wear can cause the belt to track off-center.

The tensioner and idler pulley bearings can be checked by removing the belt and spinning the pulleys by hand.

Any binding, roughness or wobble means these parts are bad and need to be replaced.

Pulley alignment can be checked by placing a straight edge against the pulleys, or with a special laser alignment tool designed for this purpose.


If they are reaching the end of their service life, replacing them now will restore the pulleys to like-new condition and reduce the risk of a breakdown because of a belt or pulley failure.

Some OEM tensioners (Chrysler 3.0L, 3.3L and 3.8L, for example) were not very robust and have experienced a high failure rate over the years.

As a result, some aftermarket replacement tensioners may not look exactly the same as the original.

A special tool that may be needed when replacing a serpentine belt or automatic tensioner on a transverse-mounted engine in a front-wheel drive vehicle is a special serpentine belt removal tool.

The tool has a long, flat extension handle that allows a socket to be placed on the tensioner bolt, so the tensioner in a tight engine compartment, can be easily rotated to relive pressure on the belt. Without this tool, the job is nearly impossible on some vehicles.

How much does it cost to replace tensioner?

Technical Editor Larry Carley contributed to this post. Read More by visiting this link: Engine-powered accessories are typically driven by serpentine belts in most late-model engines. Furthermore, the majority of individuals are aware that belts require regular maintenance and must be changed at some point. Few realize that the spring-loaded automated tensioner that maintains a serpentine belt taut is also a wear item, as it is spring-loaded and spring-loaded. As a result, when it comes time to replace the belt, it may also be necessary to repair the automated tensioner.

  • A little amount of ‘give’ is also provided by the tensioner, which allows it to absorb and cushion shock loads on the belt that occur when the A/C compressor clutch cycles on and off.
  • However, nothing lasts indefinitely, even belts and automated tensioners.
  • The belt may become cracked, glazed, and loud as it nears the end of its useful life.
  • As soon as the water pump ceases to operate, the supply of coolant is interrupted, and the engine begins to overheat.
  • When the power steering pump fails to turn, the steering becomes extremely rigid and difficult to operate at any speed.
  • In contrast, the automated tensioner is not tested to ensure that it is still in excellent operating order and in appropriate functional condition.
  • The tightness of the belt is crucial.

Slippage also causes the belt to run hot and age prematurely as a result of the heat generated.

Increased belt strain can overburden the belt as well as the shaft bearings of various components such as the water pump, alternator, power steering pump, and air conditioning compressor, potentially resulting in premature failure of these components.

The tensioners on these early systems were fixed and required human adjustment.

The spring-loaded construction avoided the need for manual adjustments and ensured that the belt tension remained constant throughout its service life.

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Despite this, the tensioner should always be checked when a belt is changed for the following reasons: Eventually, corrosion or rust will clog the tensioner housing, preventing the tensioner from moving freely.

Corrosion is often caused by road splash, which is particularly prevalent in locations where roads are extensively salted throughout the winter.

Unwanted movement caused by a loose or worn pivot arm can result in belt noise and misalignment, as well as other problems.

When the tensioner pulley’s bushing wears out, it might cause vibrations and noise to occur.

A weakened or damaged spring inside the tensioner will not be able to maintain sufficient tension, resulting in the belt slipping.

If there are cracks or damage to the tensioner housing or pulley arm, it may be impossible for it to rotate smoothly and maintain correct belt tension.

Belt glazing is a type of glazing that is utilized in belts (caused by slipping).

This indicates that the tensioner’s internal spring is weak and/or that the bushing is worn.

The tensioner pulley has a wobble in it (or idler pulley).

Belt or tensioner noise is a problem.

If you hear screaming, rumbling, growling, or chirping noises, you should investigate to find out what is causing them.

To listen for bearing noise, the probe should be put against the bolt in the middle of the tensioner pulley wheel and pressed against it.

Likewise, all engine-driven accessories (such as the water pump, alternator, PS pump, and A/C compressor) operate in the same manner.

Excessive tension or physical interference on the automated tensioner pulley might be indicated by any type of physical damage to the pulley.

It is important to check the tensioner if an idler pulley is broken because the vibrations created by a defective idler pulley might cause the tensioner to fail.

To spin the tensioner pulley center bolt, use a socket with a long handle ratchet or a breaker bar on the tensioner pulley center bolt.

If it does not move at all, the tensioner is stuck and has to be repaired or replaced.

There should be no wiggle or twist in the arm.

It’s also important to take note of how the arm on the automated tensioner is positioned.

If the position of the arm deviates from these lines, there is an issue with the arm (the belt may be too long or too short, or the tensioner may be jammed).

It is possible for the belt to track off-center as a result of misalignment or bearing wear.

Removal of the belt and manual rotation of both the tensioner and idler pulley bearings will reveal whether or not they are faulty.

Any binding, roughness, or wobbling indicates that these parts are faulty and should be replaced immediately.

It is possible to examine the alignment of the pulleys by laying a straight edge against them, or by using a laser alignment instrument that has been specifically built for this purpose.


Changing the pulleys now, if they are towards the end of their service life, can return them to like-new condition and lessen the likelihood of a breakdown due to a belt or pulley failure in the future.

Some original equipment manufacturers’ tensioners (for example, Chrysler 3.0L, 3.3L, and 3.8L engines) were not particularly durable and suffered a high failure rate throughout the years.

As a result, some aftermarket replacement tensioners may not appear to be an identical match to the original tensioners.

A unique serpentine belt removal tool may be required when changing a serpentine belt or automated tensioner on a transverse-mounted engine in a front-wheel drive car, and this tool is designed specifically for this purpose.

On some automobiles, the job would be practically difficult to do without this tool.

Serpentine Belts: The Drive’s Garage Guide

If you purchase a product after clicking on one of our affiliate links, The Drive and its partners may get a commission. More information may be found here. Although contemporary cars are complicated, they nonetheless rely on technology that have been part of humanity’s toolkit since the time of The Holy Roman Empire. Pulleys are thought to have been employed in ancient Mesopotamia, and they may still be seen today on automobile engines that are connected to various accessories and devices. The serpentine belt is responsible for connecting and concurrently encouraging all of these pulleys to work as a single unit.

It also contributes to one of the most well-known and frequently encountered troublesome automotive sounds: the squeak.

Though servicing a part that has such a wide range of implications might be intimidating, The Drive’s radioactive, sorry, hyperactive information staff can ease those anxieties with explanations, examples, step-by-step instructions, and photographs.

What Is a Serpentine Belt?

If you make a purchase after clicking on one of our affiliate links, The Drive and its partners may get a commission. More information may be found by clicking here. Although contemporary cars are complicated, they nonetheless rely on technology that have been part of humanity’s toolkit since the time of The Holy Roman Empire. In ancient Mesopotamia, it is thought that pulleys were employed, and now, they may be found on automobile engines that are connected to a variety of accessories. The serpentine belt is responsible for linking and concurrently motivating all of these pulleys as a single unit.

As a result, it generates one of the most well-known and prevalent troublesome vehicle sounds: the squeak.

Though servicing a part that has such a wide range of implications might be frightening, The Drive’s radioactive, sorry, hyperactive information staff can ease those anxieties with definitions, examples, step-by-step instructions, and photographs.

What Does a Serpentine Belt Do?

A serpentine belt distributes rotational power from one source to another through the use of pulleys and a tensioner, allowing the car’s different accessories to be powered by a single source. When the automobile is in motion, the serpentine belt is in a condition of continual rotating movement due to the rotation of the engine.

What Drives the Serpentine Belt?

One of the pulleys around which the belt is wrapped is connected to the engine’s crankshaft by a chain.

When that spins, the belt rotates as well.DepositphotosA close-up view of a serpentine belt in action.

What Accessories Does the Serpentine Belt Typically Drive?

A serpentine belt slithers over a number of pulleys, the rotational energy of which is used to power various machines. The belt is commonly used in conjunction with the following accessories:


The alternator, which is responsible for keeping your battery charged, is powered by the belt.

Power Steering Pump

The power steering pump is responsible for increasing the pressure in the hydraulic steering fluid. The driver may notice a sudden loss of power steering if the belt that drives the pump fails to operate. This will make maneuvering considerably more difficult.

Air Conditioning Compressor

Because an air conditioning compressor is responsible for distributing fluid throughout the air conditioning system, its proper operation is essential for staying cool.

Water Pump

The water pump is required by an engine in order to circulate coolant throughout the system and keep the engine’s temperature low. If the belt fails, your automobile may overheat as a result of the failure.

How Is Tension on the Serpentine Belt Created and Maintained?

Modern engines often have an automated tensioner built into their pulley systems, which ensures that the belt is kept taut by applying continuous pressure to it. The majority of current belt tensioners are spring-loaded or hydraulic, and they are equipped with dampers to ensure that the system runs smoothly. Most belt tensioners are spring-loaded, according to Depositphotos.

What Is an Idler Pulley?

To route the serpentine belt in the proper directions, idler pulleys are utilized. Because they are not linked to any other devices, they essentially do nothing but rotate with the belt and maintain it in position.

How Long Do Serpentine Belts Last?

The majority of manufacturers recommend replacing the dial as soon as the dial reaches 60,000 miles. No matter how many miles your car has traveled or how well it is maintained, you should always check your serpentine belt whenever you are under the hood. Finding symptoms that your belt is worn out just takes a couple of seconds. If it fails abruptly, you will very certainly find yourself stranded on the side of the road. If you attempt to drive with a broken belt, you run the risk of damaging the car through overheating or draining the battery.

Signs and Symptoms of a Worn Serpentine Belt

It is necessary to examine the serpentine belt on a regular basis to ensure that it remains consistently on track and in line. A regular check will also aid in the detection of a faulty belt before it fails while you are driving. There are a variety of techniques to detect a defective or soon-to-fail serpentine belt, depending on the situation. These signs and symptoms are fairly reliable predictors.


  • Fraying
  • Cracking
  • A gleaming or glossy appearance to the surface area a buildup of dirt or oil
  • A lack of tension


  • Noises such as squeaking, chirping, screeching, or rattling (which are the most prevalent)
  • A malfunctioning charging mechanism or a depleted battery The air conditioner is not working
  • Overheating

Serpentine Belt Installation

If you’ve learned what to look for in a damaged serpentine belt, you might be asking how to replace it. Making the necessary adjustments to a serpentine belt may be accomplished by anybody with a little patience and persistence. Let’s go through everything you’ll need to get the task done properly.


Time required is estimated to be one hour. The following vehicle systems are available: engine, transmission, and brakes.


It may be risky and filthy to work on your automobile, so here’s what you’ll need to make sure you leave the garage in the same condition as when you arrived.

Everything You’ll Need To Change Your Serpentine Belt

Given that we are not psychics, nor are we prying into your toolbox or garage, we’ve compiled a list of everything you’ll need to get the task done.

Tool List:

It will save you valuable time if you organize your tools and equipment so that everything is conveniently accessible. This will eliminate the need to wait for your handy youngster or four-legged assistant to bring you the sandpaper or blowtorch. (You will not require a blowtorch for this task.) Please do not allow your child to hand you a blowtorch—Ed.) As well as having a level workstation, such as a garage floor, driveway, or street parking, you’ll also need a reliable source of electricity.

Depositphotos Serpentine belts are used to drive a variety of accessories on your engine.

How To Change Your Serpentine Belt

Due to the fact that we do not know what car you drive, it is your responsibility to consult your owner’s handbook or service manual to locate the belt tensioner, identify the belt route or location, and determine exactly what you will need to remove in order to reach the belt, if anything. Let’s go ahead and do it after you’ve figured it out.

  1. Place your automobile in a safe location and open the hood to let it cool
  2. Access the belt and belt tensioner by removing any items that are in the way. Determine the location of the belt tensioner. Allowing the belt to slowly relieve pressure is accomplished with the use of a box wrench, socket wrench, or belt tensioner tool Extend the belt out from all of the pulleys and progressively loosen the belt tensioner before removing the belt altogether. The replacement belt should be wound around the pulleys following the manufacturer’s recommended course and direction. The belt will not be able to fit completely around the belt tensioner
  3. As a result, Continue to slowly compress the tensioner in order to allow the belt to be placed on the track. Release the tensioner in small increments until the belt acquires the tension. All pulleys should be thoroughly inspected to ensure that the belt is correctly installed and uniformly distributed
  4. Reinstall all of the components that were removed.

That’s all there is to it!

Serpentine Belt FAQs

You’ve got questions, and The Drive has the answers you need!

Q: Is There a Tool For Checking Belt Wear?

A:Yes! You may purchase a tiny gadget that measures the depth of the ribs on your belt. If the belt’s depth is incorrect, it is time to replace it with a new one.

Q: So What is the Proper Tension For a Serpentine Belt?

A: Every component of the belt should be taught to the point where a forceful tug is required to reveal any slack. If the belt appears to be slack or is not holding its shape, it is possible that the belt tensioner needs to be replaced. When changing the serpentine belt and tensioner, many manufacturers recommend that they be done at the same time.

Q: I’m Not a Rocket Scientist, Is It Hard To Put a Serpentine Belt On?

A: Yes, as well as no. The act of removing the old belt and replacing it with a new belt is not very difficult in and of itself. However, depending on the direction of your engine and the way it is constructed, it may be difficult to reach the parts or places that are required to complete the work successfully.

Q: But Can You Drive Without a Serpentine Belt?

A: If your serpentine belt or belt tensioner is not operating properly, we do not recommend that you attempt to drive. You should have your car towed or pushed to a safe location if you become trapped on the side of the road and need to make a repair.

Q: Then How Expensive Is It To Replace a Serpentine Belt?

The cost of a replacement belt, if you prefer to do the work yourself, ranges from $15 to $50, depending on the vehicle. However, it is advised that you replace the belt tensioner at the same time, which will add an additional $20-50 to the overall cost of the repair. If you take it to a shop, you’ll most likely pay between $100 and $200.

Q: Can a Serpentine Belt Shrink?

A:It is technically feasible, but it is unlikely to occur when you are traveling in your car under pressure. In fact, it will likely lengthen rather than shorten.

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Time Approximately one hour or less Complexity BeginnerCost$51–100


Automatic belt tensioners, which are now standard in most automobiles, make changing a serpentine belt a straightforward do-it-yourself project. In 15 minutes or less, you’ll have completed the project by following the clear photographs and step-by-step directions.

Tools Required

The bruised knuckles and cursing that went along with changing fan belts can be recalled by anyone who grew up in the good old days of doing it yourself. And to make matters worse, there were sometimes two or three belts that needed to be changed at the same time. Instead of using separate belts for each component, most automobiles today use a single wider, multigrooved ‘serpentine’ belt (also known as a serp belt), which is so named because of the way it snakes around multiple pulleys during operation.

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It is sufficient to rotate the tensioner, remove the old belt, and replace it with a new one.

Project step-by-step (11)

In order to be considered ‘excellent,’ a tensioner arm should have just a minor vibration when the arm is moved by roughly 1/32 inch or less. The belt should also be free of obvious vibration and function smoothly at all times. If the tensioner arm vibrates in a jerky manner, if the belt vibrates, or if the tensioning arm moves more than 1/4 inch, the tensioner is faulty and should be replaced. How many miles per gallon are you wasting by driving with the air conditioning on? Step No. 2

Check for smooth rotation with a serpentine belt tool

While moving the arm by around 1/32 inch or less, a ‘good’ tensioner arm should only produce a small vibration. The belt should also be free of obvious vibration and operate smoothly during the whole process. If the tensioner arm vibrates in a jerky manner, if the belt vibrates, or if the tensioning arm moves more than 1/4 inch, the tensioner is faulty and must be replaced. With the air conditioning on, how many miles per gallon are you losing? Procedure Number Two (Secondary)

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Complete your do-it-yourself tasks like an expert! Become a subscriber to our newsletter! Do It Right the First Time, and Do It Yourself! Step number three.

Check the pulley/roller

Remove the drive belt from the pulley/roller by rotating the tensioner and sliding it off. After that, turn the pulley/roller and feel for resistance, binding, and roughness on the other end of it. Afterwards, spin it and listen for any rumblings. If it does not spin smoothly or if it has a rough surface, it should be replaced. The belt should not be changed if the tensioner is faulty and the kind of tensioner being replaced is one of the more difficult styles to find and repair. To repair the tensioner, the shop would only have to remove the belt from the machine one again.

  1. The first test is a visual check while the engine is running to determine whether or not the tensioner has a dampening mechanism.
  2. Once you’ve done that, turn your attention to the belt tensioner and look for excessive movement in the tensioner arm roller (Photo 1).
  3. During cranking, the tensioner arm should revolve smoothly, and it should release without binding.
  4. After that, examine the condition of the tensioner arm pulley/roller assembly (Photo 3).
  5. If there is any noise, the tensioner should be replaced.
  6. Simple removal of the serp belt and holding bolt is all that is required to replace that style.

Afterwards, slip the replacement unit into position, making sure that the locking pin is aligned with the hole in the engine. Use a torque tool to tighten the bolt to the manufacturer specs shown in your shop manual, after which you can hand tighten it some more. Step number four.

How to tell if you need to do serpentine belt replacement

Incorporate the gauge into a belt groove by pressing it in. As long as the gauge is above the ribs, the belt is in excellent working order. If the serp belt slips down to the point where it is level with the rib, it is worn and must be replaced. 15 Car Issues You Can Diagnose (and Fix!) on Your Own Step 5: Take responsibility for your actions.

Measure wear with an app

A silver permanent marker should be used to draw a line on the belt ribs. After then, take a picture using your smartphone. According to the app, the serp belt is excellent or awful to purchase. The first generation of serpentine belts was constructed of a nitrile compound that fractured when subjected to repeated usage. In the event that your drive belt has cracks in three or more adjacent ribs within a one-inch span, or if the drive belt has four or more cracks per inch on a single rib, you should replace it.

  • Beginning with the 2000 model year, automakers began using ethylene propylene diene monomer (EPDM) belts instead of nitrile belts.
  • However, they do wear out, and the signs of that wear are far more difficult to detect.
  • It is possible to get both items for free from Gates Corporation (go to gatesprograms.com/beltwear and click on either tool).
  • But if you have a smartphone and enough maneuvering space to take a close-up shot with the engine off, you can let technology do the heavy lifting for you.
  • Always get premium belts rather than economy grade belts since you will get nearly double the mileage out of them.

The right tools make it a do-it-yourself project

Take a look at the decal that depicts the belt routing. If yours doesn’t have one, make one before you begin working on the project. Step 9: 15 of the Best Automotive Tools at Harbor Freight

Place the new belt

The new belt should be routed around the existing belt path with the use of a serp belt installation tool. While you are loading the belt around the tensioner, rotate it one more. Make a new belt and wrap it around the crankshaft pulley, then around the grooved pulleys on the transmission. Finish by sliding the belt onto a rounded, non-grooved roller to complete the operation. Double-check to ensure that the belt is in proper alignment with all of the pulleys and that it is traveling in the proper direction.

Step 11: 16 Things Your Mechanic Recommends That You Avoid Doing

Serpentine belt tool and belt placement tool

The serpentine belt may be changed much more easily with a few inexpensive specialised tools. Using standard hand tools, you can easily repair a serpentine belt. However, we do not endorse it. Spaces are frequently limited, and the belt-driven gadgets might be difficult to access. In less than 15 minutes, and without breaking a sweat, we accomplished the entire work, which was made possible by the use of a serpentine belt tool for loosening the tensioner and an alignment tool for positioning the belt (or a knuckle).

With the two extension bars, you may arrange it to reach the tensioner at the right angle, and the extra-long handle gives maximum leverage, allowing you to relieve the pressure quickly and effortlessly.

Note:If removing the serpentine belt from your automobile necessitates the removal of an engine mount, or if the belt is just practically impossible to reach, we recommend that you hire a professional to do the work. 46 Money-Saving DIY Car Detailing Techniques You Can Do Yourself

How to Replace a Serpentine Belt

  • Tools Materials: Depending on your car, you’ll need a variety of wrenches, ratchets, and sockets to complete the serpentine belt replacement.

What Is A Serpentine Belt?

Many different drive belts were used in most cars produced in the 1990s and before to carry mechanical power from the engine’s crankshaft to various auxiliary components, such as the alternator, water pump, power steering, and air conditioning compressor. When these systems were first installed in earlier vehicles, they utilised a multitude of belts of varying widths and designs, but with the introduction of newer vehicles, they were replaced with a single serpentine belt. This sort of drive belt is a flat, rubber belt that is ribbed on one side and smooth on the other, and it is used in a variety of applications.

  • Depending on the vehicle, tension is delivered to the serpentine belt either manually or by a tensioner that is either spring loaded or manually adjusted.
  • There are two different types of engine layouts, and which one your vehicle has will affect where your serpentine belt is positioned and how difficult it is to change.
  • Two types of engine layouts exist, and which one you have will affect where your serpentine belt is located and how difficult it will be to repair it.
  • This configuration places the crankshaft of the engine in the forward position, with the transmission situated behind the engine (see illustration above).
  • These automobiles will typically be equipped with a transverse engine (as seen in the illustration below), in which the engine’s crankshaft is perpendicular to the direction of travel and the engine and transmission are housed side by side in the engine bay.
  • The majority of current automobiles and crossovers are equipped with a transverse engine design, in which the front of the engine faces the side of the vehicle and the engine and transmission are positioned next to each other on either side of the vehicle.
  • maybe even for a million miles!

Is It Safe to Drive with a Bad Serpentine Belt?

After reaching the prescribed distance and the serpentine belt does not appear torn or worn, it usually doesn’t harm to put a few extra miles on it to make sure it lasts as long as possible.

All you’ll have to do is keep a closer watch on the situation. If you observe cracks in the rubber or a glazed aspect to the belt itself, it is not recommended that you continue driving with that belt in the vehicle.

What happens if I don’t do this? How bad could things get?

At the very least, a worn-out serpentine belt may make a loud screaming noise when the belt becomes wet, which might be dangerous. If the belt snaps, the car might lose power steering, air conditioning, the alternator, and possibly the water pump if it is not replaced. Overheating and probable engine damage will result if the water pump is not functioning properly.

In short, why is this job important?

Based on the usual cost to replace a serpentine belt as well as the beginner-to-intermediate skill level (depending on how simple or tough it is to access the serpentine belt), this is a work that is absolutely worth doing at your house. Performing the job yourself and purchasing a new serpentine belt from your local auto parts store may take an hour or two, but you will save money over purchasing a replacement serpentine belt.

When to Replace a Serpentine Belt?

Varying automakers, as well as individual makes and models, have different service schedules for serpentine belt replacement. In general, you’ll need to replace the belts every three to four years, depending on your vehicle. Check out FIXD if you want to keep track of key maintenance tasks such as changing the serpentine belt on autopilot while also saving time.

How do you know when it’s time to have this done or do it yourself?

The serpentine belt on a longitudinal engine is normally quite easy to replace since there is often more area to access the belt; however, transverse-mounted engines are a little more difficult to work on. You should open the hood and take a peek inside the engine compartment to assess whether or not this is a project you are willing to take on. As long as the belt can be reached without difficulty, the job should be straightforward. You might want to consider hiring a professional to replace your engine belt if your engine is transversely installed and it is difficult to remove the belt.

What Are Common Symptoms Indicating You Need a New Serpentine Belt?

  • Rumbling sounds, especially after driving across a pool of standing water or puddle
  • Cracks, obvious damage, or a glazed look are all possible outcomes. The manufacturer’s preventative maintenance program determines the number of miles driven.

Keep in Mind

Due to the fact that the serpentine belt is a worn item, you should replace it as part of the manufacturer’s suggested maintenance routine. Your owner’s handbook or theFIXD app will provide instructions on when to replace the belt, however typically manufacturers recommend changing the belt between 50,000 and 100,000 miles. Because the serpentine belt is routed across a variety of pulleys (such as the idler pulley and tensioner pulley) and components (such as the air conditioner compressor, power steering, and other components), now would be an excellent time to inspect the quality of these components.

How To Replace a Serpentine Belt

In most cases, a label is located someplace in the engine compartment that shows the serpentine belt route for the car in question. As previously demonstrated, depending on the type of car, it may display a plethora of engine possibilities. Open the hood and look under the hood for the serpentine belt routing diagram, which is normally located on a sticker under the hood towards the front of the engine compartment. When the engine is cold, start the car and turn it over. If there is no tag, consult the owner’s handbook or take a thorough photograph (or draw a hand-drawn diagram) of how the belt is attached before removing it from the vehicle.

When it comes time to put the belt back on, you will definitely want to have some form of visual reference for how the belt is routed.

Step 2: Loosen tension and remove belt

The tensioner pulley is spring-loaded, allowing the serpentine belt to be tensioned automatically without the need for human intervention. The majority of serpentine belt systems are equipped with an automated spring tensioner, while some are equipped with a tensioner that requires manual adjustment. A spring tensioner just requires pressure to be applied to it in order to release tension from the belt, allowing the belt to be removed with ease. Once the belt has been removed, you should inspect the condition of the different engine pulleys (both visually and physically).

Step 3: Route new belt and apply tension

The idler pulley can be ribbed or smooth, depending on the use (as shown above). The serpentine belt should be snaked around all of the pulleys in the order shown on the routing diagram. Smooth pulleys (such as the idler pulley depicted above) are used on the smooth side of the belt, while the ribbed side is used to wrap around grooved pulleys, as illustrated in the illustration above. Each automobile is unique in terms of the most efficient method to route the belt; therefore, starting at the bottom may be beneficial in some cases, while finishing at the lowest point, the crankshaft, may be preferable in others, depending on the situation.

Reapplying tension to the serpentine belt after it has been removed and before starting the engine, double-check that the belt is correctly routed on each pulley.

Claim Your Custom Maintenance Schedule

Today is the day to order the FIXD Sensor and free app, which will create a bespoke maintenance schedule based on your vehicle’s make, model, and miles. With automatic maintenance alerts, you’ll never miss an essential maintenance appointment again! fixd.com. Automobile fanatic throughout much of his life, with a particular fondness for offroading. I’m a former wrencher who now works as a writer, but I still like tinkering with just about anything that has an engine.


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