Convert Auto R12 system to R134a? (TOP 5 Tips)

How to Convert an R12 to the R134a System

  1. Discard any R12 refrigerant still in the system by taking your vehicle to a licensed air-conditioning professional.
  2. Open the engine compartment of your vehicle.
  3. Push the high side retrofit R134a fitting over the old fitting and use a wrench to tighten it.

Can I replace R12 with R134a?

R134a is a safer replacement for R12. Another major difference is the type of oil both refrigerators require. R12 is compatible with mineral oil, and most R12 systems use this. R134a uses Polyalkylene Glycol (PAG) oil.

How much does it cost to convert R12 to r134?

R12 to R134a Charge Conversion Formula (pounds only) Take the R12 charge specification and multiply it by 0.9. Then, subtract that result by 0.25 pounds to get the proper amount of R134a charge.

What replaces R12 refrigerant?

There are three replacement refrigerant options for R12 systems: R134a, R401a, R401b. R134a is regarded, by manufacturers and adherents to the Montreal Protocols alike, as the best replacement refrigerant.

What is the best replacement for R12 refrigerant?

The best replacement for R12 is considered to be R-134a. The chemical name of R134a is tetrafluoroethane and it chemical formula is CF3CH2F. It is a hydrofluorocarbon (HFC) and has zero ozone depletion causing potential and very low greenhouse effect.

Is it legal to sell R12 refrigerant?

Yes, you can still sell R-12 and other CFC refrigerants. Although these refrigerants can no longer be manufactured, it is perfectly legal to sell to an EPA certified buyer.

Can I still buy R12 refrigerant?

Anyone with the required EPA R-12 certification still can buy the 1-pound cans at auto-parts stores, but the cans are kept in the back and guarded like gold.

Can you put R12a in a 134a system?

Just adding R12a to a 134a system doesn’t work very well because a 50/50 mix is very inefficient. If you don’t have a vacuum pump, you can still make it work though. First warm up the car with the air on and then turn it off. Next you attach your hose to the low pressure fitting and let out all the pressure.

What year did R134a replace R12?

R12 and 134a are refrigerants used in car air conditioning systems. R12 was used in most cars and trucks until 1995 when it was replaced with 134a. Other than new car manufacturers over the last few years having switched to 1234yf, it’s remained in use ever since.

What is r414b?

R-414B (HOTSHOT)* is a blend of R-22, R-124 and R-142b with hydrocarbon R-600a (isobutane) added to improve mineral oil miscibility. This blend can be used to retrofit R-12 automotive air conditioning systems as well as stationary refrigeration systems.

When did auto AC change to R134a?

R-134a first began to see widespread usage in 1992 and took over the automotive market entirely in 1994. If you have a vehicle from 1994 or newer your air conditioning unit takes R-134a. It has been the standard automotive refrigerant for over twenty years.

Can you use R12a in a R12 system?

Adding R12a refrigerant to the R12 system: It’s basically the same procedure as adding R12 except you must screw on the R12-to-R12a quick-connect adapter fitting pictured below (included in the kit) to the LOW suction service port first. The adapter fitting has it’s own Schrader valve internally, so no gas will escape.

Can R22 replace R12?

R12 and R22 are both now banned by the EPA in the United States. Other more environmentally friendly alternatives exist, but even those cannot be changed in air conditioners or other refrigeration units with R12 without a thorough cleaning of the unit.

Convert Auto R12 system to R134a

Converting your car’s old R12 system to an R134a system may be accomplished in two ways: the factory approach and the simple method. The factory technique is the greatest option because you will be replacing parts that are most likely leaking as a result of wear and tear. Furthermore, employing the factory technique will result in the optimum AC performance. Unfortunately, it will be more expensive and time demanding in the long run.

First step to convert your auto R12 system to R134a

Because R134a increases discharge pressure, it increases the work load on the compressor. Some older compressors are unable to cope with the additional load. If your car is equipped with a Harrison DA6, swap it out for an HD-6, HR-6, or HR-6HE. If your car is equipped with a Ford FX-15 compressor, swap it out for an FS-10 compressor. Retrofitting a compressor

What you need to convert R12 to R134a using the factory method

Parts and materials for retrofitting 1) Kit for flushing the air conditioning system 2)Full HNBR O-ring set for your automobile. 3)R134a conversion package, which includes R-134a port adapters, oi, port covers, and a retrofit label 4)Pressure switches for R134a 5)R134a orifice tube (optional). 6)New barrier type hoses for vehicles manufactured prior to 1990. 7)A new R134a accumulator/dryer was installed. The manufacturing process of converting R12 to R134a is demonstrated here. The R12 should be discharged, and then the R12 should be recovered for recycling.

  • 3) Flush the high pressure and suction pipes of the air conditioning system to eliminate mineral oil.
  • 5)Inject the compressor, condenser, and evaporator with the prescribed Ester or PAG oil in the right viscosity.
  • 7) Remove the accumulator/drier from the system.
  • 9)If your car is older than 1990, swap out the hoses.
  • 11)Connect the vacuum pump and manifold gauge to the vacuum system and pull a vacuum for a minimum of 45 minutes.
  • Attach the high and low port adapters, if necessary.
  • 15) Installation of the port caps (15) 16.
  • 17.

Calculate how much R134a to use

Given that R134a is LIGHTER than R12, you must adjust the charge weight to ensure that you receive the right charge throughout your refit. Fill the system with 75 to 85 percent of the factory-specified capacity in order to get the optimum cooling performance possible. Use this algorithm or the chart below to calculate your score. Calculate the refrigerant capacity of your present system by multiplying the R12 charge standard by 0.9, and you have your refrigerant capacity (90 percent ). Then remove 1/4 (0.25) pound from the total.

In addition, R134a has a lower tolerance for over- and undercharging than other gases. In fact, adding too much R134a refrigerant can DECREASE the effectiveness of your air conditioning system. That is diametrically opposed to R12.

R134a retrofit capacity chart

To determine the refrigerant capacity of YOUR car, please visit this page. Conversion Table for the R12 to R134a Retrofit Charge

What you need to convert R12 to R134a using the Quick/Easy

Retrofit package for R134a that includes R-134a port adapters, oi, port covers, and a retrofit label. 2)Pressure switches for R134a

Here’s how to convert R12 to R134a with the factory method

The R12 should be discharged, and then the R12 should be recovered for recycling. Add the required quantity of PAG or Ester oil, then swap out the high and low pressure switches, then attach the high and low port adapters, then turn on the engine. 5)Connect the vacuum pump and manifold gauge, and pull a vacuum for at least 45 minutes at a time. Incorporate R134a according to the retrofit formula/chart shown above. Incorporate the port covers into your system. 8 Attach the retrofit sticker to the system in order to alert future service professionals that the system has been changed to R134a.

Rick Muscoplat posted a blog entry on

How To Convert Your Car AC R12 System To R134a (4 Steps)

If you drive a car that was built before 1994, it’s likely that the air conditioning system is still utilizing R12 to cool the vehicle. According to the Environmental Protection Agency, this refrigerant is hazardous to the environment and must be replaced with R134a instead. You may, however, be unfamiliar with the process of converting your car’s R12 air conditioning system to R134a. You must first properly dispose of the old R12 refrigerant and then retrofit the air conditioning system with ports and equipment that are compatible with the old R12 refrigerant.

In this post, we will look at how to calculate the optimum quantity of R134a to use in your system.

How to Calculate How Much R134a is Needed

The R134a refrigerant is much lighter than R12. You must fill the new system with between 75 and 85 percent of the factory-set capacity for optimal cooling in order to guarantee that the proper charge is applied. To figure out the refrigerant capacity, you’ll want to start with the specifications for the present system and multiply the R12 charge by 0.9, or 90 percent. To get this figure, subtract 14 or 0.25 pounds from the total. R134a, on the other hand, will not cool at the same rate as R12.

R134a, on the other hand, is significantly more forgiving of both under and overcharging.

How to Convert Car AC R12 to R134a

The following procedures will show you how to simply convert your R12 to R134a in an older vehicle. This is not the best method of converting your system because you want to replace all of the O-rings and install a new accumulator, filter, and other components. However, because we’re talking about a cost of more than $ 2000, it’s probably not worth it if your automobile is more than a decade old. There are conversion kits available for many different automobile types, which comprise all of the essential components for the conversion.

However, simply changing the fittings and adding the appropriate amount of R134a will work on the majority of automobile types, but it will not provide a long-term solution. If you do this, we strongly advise against it, and you do so entirely at your own risk:

1. Discard R12

Before you do anything further, you must remove the R12 refrigerant that is currently present in the system by pumping it out. Always get this done by a licensed expert since it must be disposed of in the appropriate manner. R12 might cause serious problems if it is accidentally released into the environment. Not only is it harmful to the ecology, but it is also against the law.

2. Retrofit the System

New fittings must be installed on both the low and high side service ports of the air conditioning system. Replace the old component with the low side fitting by turning it over. To tighten it to the manufacturer torque specifications, you’ll need a wrench. Place the high-side fitting over the old connector and tighten it down. Tighten this down to the proper specifications as well with a wrench, of course. You want to include the retrofit label on the connections so that other individuals who purchase the car after you are aware that R134a is being used.

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3. Hook up Gauges

Close all of the valves on the manifold gauge so that it is completely empty. Connect the low-side port to the blue hose and the high-side port to the red hose to complete the connection. The vacuum pump is connected to the yellow hose. Start the pump and open both of the gauges’ valves at the same time. At the very least, you should vacuum the system down for an hour. Close all of the valves and switch off the pump after you’re finished with the job. RELATED:AC Low Side Pressure and Excessive Side Pressure – Common Causes Repair Expenses

4. Pump in R134a Refrigerant

Connect the R134a can with the yellow hose that is provided. This refrigerant should already be lubricated with petroleum. In every other case, you will need to include it individually. To open the can, turn the valve on the top of the can. Start the automobile motor and crank up the air conditioning to the highest setting possible. A thermometer can be placed in the vent to measure the temperatures that are being blown out. You want to open up the system so that the refrigerant from the can may be drawn into the system using the blue hose linked to the low side port.

When you’re finished, shut the valves on the gauges and remove them from the circuitry.

Cost of Converting an R12 to the R134a System

A expert will convert the R12 gas to the more energy-efficient R134a gas, which will cost you around $250. Although this is more expensive than replacing the complete air conditioning system, it is far more cost-effective.

A R134a system installation would cost between $2,000 to $4,000, depending on the size of your home. In most cases, it is not worthwhile to proceed down this road, especially when it is possible to simply refit the current equipment.

R12 to R134a Conversion Chart & Formula

When converting a unit from R12 to R134a refrigerant, it is necessary to modify the charge to account for the change. If the same quantity of r134a refrigerant is used, it will be lighter than the same amount of r12 refrigerant. This is not only necessary to know when working on commercial refrigeration systems, but it is also critical to know while working on HVAC equipment and even automobiles. Fortunately, we have an R12 to R134a conversion chart and formula that we can use to adapt our systems properly.

R12 to R134a Charge Conversion Formula (pounds only)

When converting from R12 to R134a refrigerant, it is advised to use a charge level between 75 and 85 percent of the original charge. There is a simple method to use to compute the difference in charge level if no conversion information is given. When the R12 charge standard is specified in pounds, this method will work. Take the R12 charge specification and multiply it by 0.9 to get the R12 charge specification. To determine the correct quantity of R134a charge, subtract the result by 0.25 pounds and multiply it by the result.

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Take, for example, a 2 lb charge standard for R12, which is stated on the R12 website.

This means that a charge level of 2 lbs.

for R134a.

R12 to R134a Refrigerant Charge Conversion Charts

You may be pressed for time and require a speedy response, despite the fact that the technique above is beneficial. The following is a PDF of tables that demonstrate the conversions of R12 to R134a refrigerant charges in pounds and ounces: Conversion Tables for R12 to R134a in Pounds and Ounces

Additional Info from the Forum

A member of our community, Fixbear, offered some valuable advice during a debate on the conversion of R12 to R134a gas. In addition to providing a complete conversion chart (in ounces), he also included the following point to consider: When compared to equipment constructed for R-12, equipment built for R-134a will be a little too small in terms of size. An R-134a system will require a larger compressor as well as larger heat exchangers in order to perform the same tasks. An air conditioning system that is converted from R-12 to R-134a will have decreased capacity (will need to operate longer) and will most likely create greater head pressures as a result (not enough condenser area).

Converting an R12 System to an R134 System ❤️ What You Should Know

On a hot day, there is nothing more frustrating than having your car’s air conditioner break down. One of the primary benefits of having a car is the ability to go about town while being cool and comfortable. It is extremely expensive to repair an air conditioner, and in many circumstances, replacing an air conditioner will cost more than the value of your vehicle. Automobile repairs are EXTREMELY EXPENSIVE. If your vehicle’s air conditioning system isn’t keeping you as cool as it used to, it may be necessary to recharge it.

A R12 refrigerant may be present in the air conditioning system of a vehicle that was constructed before to 1995. This means that you will have to switch the refrigerant system to an R134a system if this is the case.

What is R12 Refrigerant?

R12 is a refrigerant that is often found in household refrigerators and freezers. It was originally employed in the manufacture of household air conditioning units and car cooling systems. A collaboration between General Motors and Dupont was the inspiration for it in the 1920s. It was used for residential refrigeration until the 1950s, when it was subsequently superseded by R-22, which was less demanding on compressors and hence more environmentally friendly. The Environmental Protection Agency ordered in 1994 that all new automobiles utilize R-134A refrigerant rather than R-12 refrigerant, and this requirement continues today.

Why it is Dangerous

The Environmental Protection Agency (EPA) identified chlorine in the R-12 refrigerant, which causes severe harm to the ozone layer. The use of R-12 in a vehicle is prohibited in certain areas, and you must be a licensed mechanic or other automotive specialist in order to purchase the substance. If you use R12 refrigerant today, you will be in violation of Title VI of the Clean Air Act, which prohibits the release of pollutants into the environment. Civil penalties and criminal prosecutions are among the options for enforcing the law.

In the event that a firm is found to be in violation of refrigerant rules, the penalty might be quite high.

If you are detected using the refrigerant, you will not be sentenced to millions of dollars in fines, but you will be arrested and fined.

How to Convert the Refrigerant

. Anyone with a few simple tools and a little know-how may easily recharge the air conditioning system in their car. With the use of a basic automotive tool kit and a few replacement parts, a car owner may convert an R12 system to an R134a system in about an hour. Any R12 refrigerant that remains in the system will need the vehicle to be towed to a professional air-conditioning technician. If you try to do it on your own, you may end up with a hefty fine. You can begin working as soon as the R-12 is no longer present.

Safety First!

When the system is charged, do not open the valve that is linked to the high-side service port on the system. The gas within is pressured and has the potential to detonate.

Tool for the Job

  1. When the system is being charged, do not open the valve that is attached to the high-side service port. It has a pressurized gas in it that has the potential to blow up at any time.


Open the hood of the car and look for the high and low side service ports of the R12 air-conditioning system on the inside of the car. Press down the low-side retrofit R134a fitting, which is designed to fit over the existing fitting, and tighten it with a wrench. The fitting should be torqued to a torque of 20 foot-pounds (foot-pounds).


Place the high side retrofit R134a fitting on top of the old fitting and press it down firmly to secure it in place.

Using a wrench, tighten it down. It has to be torqued to a maximum of 20 foot-pounds. You will be required to display a sticker in a prominent location on the engine, stating that you have converted the vehicle to run on R134a.


Inspect your manifold gauges and make sure that all of the valves are closed. A red hose, a yellow hose, and a blue hose will all be visible on the scene. The blue colored hose should be connected to the low side port, and the red colored hose should be connected to the high side port. Connect the yellow hose to the vacuum pump on your vacuum cleaner. Start the vacuum pump and open the high and low valves that are located on the manifold gauges to allow the vacuum to escape. Allow at least one hour for the pump to operate.


You will now wish to connect the R134a lubrication container to the yellow hose that has been provided. Open the low-side valve and allow the vacuum to draw the oil into the system. The amount of oil you need to add should be specified in your vehicle’s owner’s handbook, if one is available. Depending of the refrigerant, you may not be required to apply any oil at all.


Your vehicle’s owner’s handbook will tell you exactly how much R12 refrigerant it needed in order to operate at peak performance. You should use 10 percent less R134a refrigerant than the manufacturer’s recommendations in the owner’s handbook. Keep in mind that underfilling the system will cause the compressor to malfunction. If you overfill the system, it is possible that the seals will begin to leak as well. All of the valves on the manifold gauges should be closed. You should now remove the valves from the system.


Connect a can of R134a refrigerant to the T-valve using a hose clamp. Start the engine and crank up the air conditioning to the maximum setting. A thermometer should be placed in the central vent. This will keep track of the temperature as you add refrigerant to the system.


Connect the T-valve hose to the service port on the low side of the valve. Open the valve to allow the refrigerant to be sucked into the system by the system. You should be able to feel the can getting cooler as it gets closer to you. It should also have a sense of emptiness. Allow for five minutes of draining time. After that, you’ll want to check the temperature of the air inside the vehicle. You will continue to add refrigerant until the total volume of the system is 10 percent less than the maximum system volume.

Check for leaks and make sure there are none.

Cost of Converting an R12 to the R134a System

In most cases, having a repair convert your air conditioning system will cost you around $200. If you wish to replace the air conditioning system in your car, the cost will range between $1,500 and $4,000, with an average cost of $2,750. On those who want to have a professional do work on their vehicle, they will have a variety of alternatives for where to get the job done.

Taking Your Car to an Auto Body Shop

Auto body shops are the most reliable source for routine maintenance and the vast majority of repair needs. They will not charge you as much as a dealership mechanic, and you will be able to communicate directly with the technician about your vehicle’s problems. It is critical to choose a reputable retailer. On the AAA website, you may discover a list of several certified car body businesses.

It should be possible to locate a mechanic in your area. Make certain to inquire about the mechanic’s licensing and certification, as well as to obtain a written quotation for the repairs. Make sure they have positive evaluations on Angie’s List by searching for them on the website.

Taking Your Car to the Dealership

Auto body shops are the most reliable source for routine maintenance and the vast bulk of repair work. They will not charge you as much as a dealership mechanic, and you will be able to communicate directly with the technician about your vehicle’s needs. Picking a reputable store is essential. On the AAA website, you’ll discover a list of several certified car body businesses. An auto mechanic should be easy to locate in your area. Make certain to inquire about the mechanic’s licensing and certification, as well as to obtain a written quotation for the work.

Use Your Car as a Trade-in

You will receive a trade-in allowance for your old automobile if you are planning to purchase a new one, and the salesman will offer you a certain amount of money in exchange for your old vehicle. They will almost certainly give you less money than the vehicle is worth. They will rely on the fact that you are too lazy to try to sell your vehicle to anybody else. It’s also possible that they will give you an apparently reasonable price for your old automobile. If they do this, make sure to thoroughly read all of your papers.

When you visit the dealership, you should refrain from informing them of your previous vehicle.

When considering a trade-in, it is always a good idea to visit the Cash Cars Buyers website and allow us to make you an offer before proceeding.

Donate Your Car

Some charity groups will accept your vehicle as a contribution, and others will not. In exchange for your cooperation, they will provide you with a tax deduction equal to a percentage of the car’s market worth. Giving to charity is usually a good thing; but, in this situation, the organization will just sell the automobile and pocket the proceeds. Instead of donating your automobile to them, it may be preferable to sell your car and contribute the proceeds to the charity. They will still receive the funds, and you will still receive a tax deduction, but you will spare the charity a step in the process.

Sell Your Car Online

When you search for ‘sell my car,’ a list of websites that will allow you to sell your vehicle will surface. These websites will let you to post your vehicle on their website for a monthly charge. You will be competing against a large number of other individuals, and it may take a long time to sell your vehicle in this manner. In the event that you do have a prospective buyer, you will need to set up some time in your schedule to display the vehicle. It’s possible that you’ll have to show the automobile multiple times before it sells.

People who react to your advertisement may only be interested in specific components of the vehicle.

It is not always a smart idea to meet up with someone you have met on the internet. A large number of offenders locate their victims through the use of internet bulletin boards. It’s possible that you’ll wish to meet prospective purchasers somewhere other than your house.

Sell Your Car to Us

Cash Cars Buyers is the easiest option to earn cash for your junk or old vehicle. There is no faster or more convenient way to get money for your vehicle than selling it to them. Our procedure is straightforward. Simply fill out our online form and we will contact you with a quote as soon as possible. We require the following information from you: your name, email address, and phone number. We’ll also need to know the brand, model, year, VIN number, and mileage of the vehicle in addition to its location.

  • In the absence of your vehicle’s title, you will be unable to sell it to a person or trade it in for anything.
  • You will be required to pay a charge and wait many weeks before receiving your pink slip.
  • We only require the registration and your driver’s license.
  • Arriving on schedule, doing a quick examination, paying you in cash, and towing away your unwanted scrap will be our responsibility.

r12 to r134a conversion kit

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A 5% discount is applied at the time of purchase.

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Ships to the Netherlands are available.

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How To Convert R12 To R134a With 7 Quick Steps: Conversion Chart & Formula

Read for 3 minutes If you have an older vehicle (pre-1994) and your vehicle’s air conditioning system uses R-12 refrigerant, you should consider replacing it. In this case everything is in working order; there are no leaks, the system has a normal quantity of refrigerant, and the system is appropriately cooled. As a result, you will not be required to upgrade your air conditioning system to R-134a. However, if the air conditioning in your automobile is not working properly, you will need to upgrade to the R134a system.

Fortunately, you have arrived at the correct place for converting the R12 system to the R134a system.

How To Convert R-12 To R-134a System

Read for three minutes In the case of an older vehicle (pre-1994) with an R-12 refrigerant system in the automobile air conditioning. In which case everything is in working order; there are no leaks, the system has a normal quantity of refrigerant, and the system cools as intended. As a result, you will not be required to upgrade your air conditioning system to R-134a gas. The R134a system, on the other hand, must be used if your car’s air conditioning system is having trouble. The reason for this is that the refrigerant R-12 has been prohibited and is thus unavailable on the market.

A conversion chart and a conversion formula are included in this comprehensive tutorial, which teaches you how to convert an R12 system to an R134a system in just seven simple stages.

1. Discharge The R-12 Refrigerant:

Taking the Refrigerant Out of Service

  • Remove all of the old R-12 refrigerant from the system
  • Recover the R-12 refrigerant so that it may be recycled.

2. Flush The Whole System:

  • Remove all of the oil and pollution from the area
  • Ensure that the whole system is free of mineral oil and debris, with no traces of R-12 remaining
  • Flush the AC pressure lines.

3. Retrofit The R-134a System Parts:

  • Retrofitting the R-134a system components, particularly the receiver drier and pressure ports, is recommended. A bigger receiver drier and new filling ports are required for the R-134a system because to the increased size of the refrigerant.

4. Evacuate The System:

Taking Care of the Air Conditioning System

  • Incorporate the vacuum gauge and thoroughly purge the system of any air and moisture
  • Make sure the vacuum is on for at least 45 minutes. Look for any leaks.

5. Charge The System:

Charging the Air Conditioning System

  • First and foremost, ensure that the right volume of Ester lubricating oil is used. Then, fill the system with R-134a refrigerant until the desired cooling is achieved. The following method may be used to determine the precise quantity of refrigerant to be used, or you can use the chart to determine the amount of refrigerant to be used if you do not know how much refrigerant to use.

6. Install The Port Caps

Examining the AC Leak

  • To check the port cap, put it on and drive about
  • It is advisable to perform a road test.

7. Attach The Warning Labels:

R-134a Poison Alert Label

  • On alert the technician of future servicing, attach the R-134a retrofit warning sticker to the R-134a retrofit.

R-12 To R-134a Refrigerant Conversion Formula

Due to the fact that R134a is lighter than R12, the same amount of R134a weighs significantly less than the same volume of R12. As a result, when changing from an R12 to an R134a system, it is critical to understand how much r134a refrigerant will be required. To be able to calculate exactly how much refrigerant to install, you must first understand the formula. To calculate the desired amount, first determine how much r12 refrigerant your system consumes. Then multiply the result by 0.9 and remove it by 0.25 to arrive at the desired value.

R-12 To R-134a Refrigerant Conversion Chart

Refrigerant Conversion Calculator for R-12 to R-134a (Source ricksfreeautorepairadvice)

R-12 to R-134A Refrigerant Retrofit

Manuals, Auto Parts, Accessories, Tools & Auto Repair Library are all available here. Books, Car BLOG, Links, and more Index byLarry Carley (c)2019 All rights reserved. The air conditioning system in an older car (pre-1994) may use R-12 refrigerant, which is harmful to the environment (Freon). As long as the air conditioning system does not have any leaks and is properly cooling, there is no reason to switch from R-12 to the new ‘ozone safe’ R-134a refrigerant. However, if your A/C system has lost its charge as a result of a leak, accident damage, or the necessity to access it in order to repair a compressor, hose, or other component, you may need to convert from R-12 to R-134a while recharging your vehicle.

Because R-12 is no longer manufactured in the United States, There are still supplies of recycled R-12 available, and some R-12 is still being imported from outside producers.

However, it is difficult to come by and is prohibitively costly. As a result, many customers simply recharge their older R-12 air conditioning system with R-134a after they have had repairs completed on their unit.

R-134a Retrofit Conversion Costs

Is it cost-effective to refit an older car with R-134a if the vehicle’s air conditioning system has lost its refrigerant charge or requires extensive repairs? Vehicles deteriorate at a faster rate as they become older. It is possible that it will be worth only a few hundred dollars when it is 15 or more years old. Many owners will not spend any more money into an older car unless the repairs are absolutely essential in order to keep it on the roads. Even in such case, it may be cheaper expensive to just dispose of the car or to junk it than than to repair it.

Summer heat and excessive humidity may make driving in city traffic uncomfortable, especially during the daytime.

You may, however, save money by performing part of the work yourself on many older vehicles if you have the necessary knowledge and tools.


There is absolutely no reason to convert a car from R-12 to R-134a as long as the R-12 system is functioning correctly and holds a regular charge of refrigerant. When charged with R-12 refrigerant, air conditioning systems that were intended to use R-12 will perform optimally. It is normally preferable to fix leaks and recharge the system with R-12 rather than replacing the system entirely if a leak is discovered. Converting to R-134a normally results in a little reduction in cooling performance, and depending on the vehicle model year, it may need some further adjustments.

According to the Mobile Air Conditioning Society (MACS), the typical repair fee for a retrofit when other A/C repairs are required is around $100 in addition to any other repairs that may be required (such as replacing the compressor, condenser or evaporator, etc.).

As long as the vehicle is equipped with barrier-style hoses, as well as a compressor and seals that are compatible with R-134a, the only thing that has to be altered is the compressor lubricant.


Retrofitting can be accomplished in one of two methods. The first step is to adhere to the refit technique provided by the car manufacturer. This generally entails removing all of the old mineral oil from the system, replacing the accumulator or receiver/dryer with one that contains X-7 desiccant, replacing O-rings (if necessary), installing or replacing a high pressure cutout switch (which many shops seem to forget about), changing the orifice tube or expansion valve (if necessary), adding the specified PAG oil, and recharging the system with R-134a, among other things.

It may be necessary to upgrade to a more energy-efficient condenser in some applications in order to achieve better cooling performance.

Federal legislation also requires the permanent installation of R-134a fittings on the high and low service ports in order to prevent the possibility of refrigerant cross-contamination the next time the vehicle is serviced, according to the manufacturer.

Labels must also be put on the system to indicate that it has been switched to use R-134a gas.

OEM R-12 to R-134a Retrofit Bulletins

When the automobile industry made the switch to R-134a back in 1995-1995, all of the major manufacturers issued Technical Service Bulletins that detailed upgrade procedures for their different makes and models of vehicles. These extensive bulletins are still available on the different OEM Technical Service websites, however it may take some effort to find them; most of these websites require a fee to view them. Click Here to see an example of a Toyota Technical Service Bulletin that covers R-12 to R-134a conversions on their vehicles.

A minor subscription fee is also charged by certain websites.

Most auto parts stores carry these adapters, which are inexpensive.

Basic ‘Generic’ Retrofit Procedure that Works on Most Vehicles

The ‘fast and inexpensive’ technique to retrofitting is the second option available. It is possible to convert R-12 air conditioning systems on many 1989 to 1993 model year vehicles by simply recovering any remaining refrigerant, adding POE oil (which is compatible with both types of refrigerant), and recharging to 85 to 90 percent capacity with R-134a after the vehicle has been driven for a period of time. It is possible that a simple retrofit will cost no more than a few cans of refrigerant and a small amount of compressor oil – assuming that there is nothing else wrong with the A/C system.

  1. Any compressor equipped with Viton seals is ineligible for retrofit installation.
  2. The compressor on these vehicles must be changed.
  3. In addition, because R-134a causes higher compressor discharge pressures and increases the compressor’s work load, some lightweight compressors may not be durable enough to withstand R-134a over an extended period of time.
  4. In place of the Harrison DA6, an HD-6, HR-6, or HR-6HE compressor might be used instead.
  5. The cooling performance of the system will vary based on the architecture of the system, regardless of whether retrofit technique is employed.

It is more likely that systems with big or efficient condensers would see less of a loss in cooling performance while operating with R-134a than systems with smaller or less efficient condensers.


When upgrading an older R-12 system to an R-134a system, one method of improving cooling performance is to install a ‘variable valve’ orifice tube in place of the normal fixed orifice tube, as shown in the diagram. These aftermarket variable orifice tubes allow the flow rate through the valve to alter, resulting in improved cooling at idle and low speeds as compared to stock tubes. As much as 5 to 8 degrees can be reduced in the A/C outlet air temperature with this type of valve. This makes a significant impact while the car is crawling along in stop-and-go traffic in the city.

  • Many older rear-wheel drive automobiles and trucks do not have an electric fan for the A/C condenser, which is a safety hazard.
  • Installing an auxiliary fan that activates when the air conditioner is switched on will provide the additional airflow required to transport the heat away.
  • Check to ensure that the new unit has the same BTU rating or a higher BTU rating than the original condenser or evaporator if the original unit was replaced due to a leak, damage, or fault.
  • When a compressor fails, it might release metallic debris into the system, which can cause damage.
  • It is possible to flush parallel flow condensers by using refrigerant or an authorized solvent to remove the majority of the debris, although this is not an effective method for flushing.
  • Most experts additionally advocate adding an in-line filter (high side and/or low side) to protect the new compressor, as well as the orifice tube or expansion valve, during the installation process.


Alternative refrigerants other than R-134a are not approved for retrofitting into vehicles by the car manufacturers. However, there are a range of alternative refrigerants that fulfill the Environmental Protection Agency’s (EPA) SNAP (Significant New Alternatives Policy) requirements for admission into the environment. The majority of them are mixes that are designed to be used in older automobiles to replace R-12. WARNING! Some so-called drop-in replacement refrigerants for older R-12 systems include flammable hydrocarbons, making them unsuitable for use in confined spaces (propane, butane, isobuane, etc.).

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OZ-12, HC-12a, R-176, and R-405a are some of the goods in this category.

According to the Environmental Protection Agency, a spark from a cigarette or a switch might ignite leaking refrigerant, resulting in an explosion and fire.

They further claim that the Environmental Protection Agency’s position on their product is unreasonable, and that HC-12a has been effectively utilized in various car A/C systems across the world with no accidents or injuries as a result of the ignition.

Despite this, we do not encourage or promote the use of combustible refrigerants in any way. Flammable Refrigerants.


Despite the fact that R12 is no longer made in the United States, it is still produced in other nations. We’ve received multiple instances of bootleg R-12 being imported into the United States from Mexican sources. Bootleg R-12, if available, eliminates the need to adapt your air conditioning system; nevertheless, we caution that the purity and quality of bootleg R-12 are questionable. It frequently contains additional refrigerants (such as R-22 and R-134a), flammable hydrocarbons (such as propane, butane, and other similar substances), moisture, and air.

Because of these factors, we do not suggest bootleg R-12.


It’s crucial to note that R-134a or any other alternative refrigerant cannot be combined with R-12 or used to top off an R-12 system, which can lead to serious consequences. Any R-12 that remains in an air conditioning system must be removed using appropriate recovery equipment (venting is not permitted) before a new refrigerant can be introduced into the system. To avoid cross-contamination of refrigerants as well as cooling performance issues, this is an absolute requirement! Mixing various refrigerants can result in serious consequences.

This can result in a reduction in cooling performance as well as an overstressing of the compressor to the point where it malfunctions.

As a result, if someone recharges an R-12 system with R-134a without also adding an appropriate lubricant, the compressor will fail within a few months.

  • R-12 and R-134a were found in 57 percent of the samples (an increase of 10 percent from the previous year)
  • R-22 was found in R-12 systems in 20% of cases. Twenty percent of the samples included two or more refrigerants combined together
  • Hydrocarbons (propane or other flammable hydrocarbons) accounted for 30% of the total amount. 2 percent had an excessive amount of air

R-12 and R-134a were found in 57 percent of the samples (an increase of 10 percent from the previous year); and R-22 was found in R-12 systems in 20% of the cases analyzed. Two or more refrigerants were combined together in 20 percent of the cases. Hydrocarbons (propane or other flammable hydrocarbons) accounted for 30% of the total amount; There was too much air in 2 percent of the samples.

More Air Conditioning Articles:

Problem with the air conditioning cooling system: it only blows warm air. There is no cool air. Identifying and Troubleshooting Air Conditioning Issues Automatic Climate Control System (A/C) Troubleshooting Troubleshooting Problems with the A/C cooling system due to temperature How to Recharge the Air Conditioning in Your Car. Contamination of the Refrigerant Alternative refrigerants are those that do not include chlorine or bromine. New Refrigerants for Automobiles A/C Refrigerants that are flammable Failures of the compressor Recommendations and Precautions for Air Conditioning Compressor Oil Flushing the A/C condenser More Carley Automotive Technical Articles may be found by clicking here.

Offsite R-12 Retrofit Resources: Acura Retrofit is a website dedicated to Acura retrofit procedures. Chrysler Retrofit is a website dedicated to Chrysler retrofit procedures. – Ford Retrofit Procedures for General Motors Retrofits ( Procedures for Toyota Retrofitting The following are recommendations for converting R-12 Sanden compressors to R-134a.

Converting older General Motors automobiles from R-12 to R-134a Make sure to check out our other websites as well: You Can Do Your Own Auto Repair AUTOMOTIVE SOFTWAREOBD2HELPRandom-MisfireScan Tool HelpTROUBLE-CODES Carley Automotive Software

Retrofitting R12 to R134a by Classic Auto Air

With the phase-out of R12 (which began on January 1, 1996), various concessions have been made in order to transition to R134a. Even alternatives such as ternary mixes need the replacement of components such as ‘O’ rings on certain systems, filter dryers, and accumulators, which are not available as a ‘drop-in’ replacement.

System lubrication:

When converting R12 vehicle air conditioning systems to work on R134a refrigerant, the vast majority of car manufacturers recommend PAG (Poly Alkaline Glycol) oil as the only oil replacement. Ariazone also suggests POA oil, which is a wholly synthetic oil that is good for all compressors, as well as for the refrigerants R12 and R134a, according to the company.


Considering the cost of an R134a conversion will be a critical consideration, but don’t sacrifice performance and dependability for the sake of saving money. The system will experience small temperature and pressure changes, which will be reported in greater detail. This will all be determined by how well the A/C system operated on R12 in the first place. Changing from R12 to R134a will not increase the performance if the performance was already marginal on R12. Your best choice is to replace your old, worn-out system with a Classic Auto Air Perfect FitTM system, which is more energy efficient.

All of the components are of the highest possible level of quality.

All Classic Auto Air installation kits come with comprehensive instructions to make the process as simple as possible.

Retrofitting the A/C system is probably the simplest part. The most important part prior to retrofitting will be the time spent talking to the owner discussing:

  • What type of A/C repairs were performed most recently and when
  • What parts were changed
  • Existing alternative refrigerant is being used by the air conditioning system. Is the A/C working/operating well at the moment? Whether not, inquire with the owner if there has been a known history of difficulties. For how long do they expect to keep the car in storage? Do you plan to replace the condenser with a more energy-efficient model? Inform the proprietor of the associated costs
  • What type of warranty will be provided for the retrofit
  • And Before the R134a retrofit can be completed, any faults or leaks will need to be rectified.
  1. A thorough visual check of all components, including hoses, for signs of leakage or corrosion
  2. Also, search for warning markings stating what refrigerant is now in the A/C system, since an alternate refrigerant may have already been utilized.


  1. Tune-up — Start the engine, engage the air conditioning, and run it for 10 minutes at 1500 rpm, maximum cooling, and the highest fan speed possible. Insert a thermometer probe into the center vent and attach the R12 pressure gauges to the engine. Install enough R12 refrigerant (if available) to bring the A/C system pressures and center vent temperatures up to the manufacturer’s standards, if necessary. Preserve a record of the pressure and temperature measurements

It is important to note that using the air conditioning system for 10 minutes, or longer, will ensure that the majority of the mineral oil is trapped in the compressor. If there are any indicators of system overheating, check the airflow through the condenser for obstructions/restriction, such as bug screens or grass seeds on the condenser face, as well as any signs of system limitation.

  1. Leak checking — Using a specialized R12 leak detection instrument, do a comprehensive leak check (in accordance with SAE J1627). (According to SAE J1627)
  2. The recovery of R12 from the A/C system is accomplished by employing a specific R12 recovery device (according to SAE J1990 standards). Remove the components that will be changed as part of the R12 upgrade to R134a, as indicated by the A/C system or vehicle manufacturer’s specifications
  3. R12 parts replacement


  • Filter drier or accumulator
  • ‘O’ rings on the high side of the system running through to the evaporator’s intake
  • And Then, add 30-50ml of PAO oil to the a/c system. Install R134a charging port adapters on the high and low sides (apply a thread lock to fasten to R12 charging ports)
  • Warning labels that have been retrofitted
  1. Filter drier or accumulator
  2. ‘O’ rings on the high side of the system running through to the evaporator’s intake. Then, add 30-50mL of PAO oil to the a/c system. Install R134a charging port adapters on the high and low sides (thread lock is required for R12 charging ports)
  3. Warning labels that have been retrofitted.

R134 Conversion – Think Twice Before You Do It

André Clemente is the founder of New Old Cars, LLC, which is licensed by the Environmental Protection Agency (EPA) (Mobile Vehicle Air Conditioning) The most recent update was made on July 26, 2020. Are you considering upgrading the air conditioning system in your old automobile from R12 to R134a? First and foremost, it’s likely that your automobile has already been switched from R12 to R134a and you are completely unaware of this. Simply taking a glance at the service port fittings will reveal whether or not your system has undergone conversion.

  • However, if you want to go the extra mile in preserving the uniqueness and worth of your automobile (and you have the extra funds to do so), there are a number of compelling reasons to refrain from doing this alteration.
  • R12 has the ability to blow 6 to 7 degrees colder than R134a while also being 15% more efficient.
  • The upshot is that an R12 system that is in fine working order will blow colder and drop temperatures faster than a system that has been changed to R134a.
  • Many of the individuals who say that their air conditioning ‘blows colder’ after switching from R12 to R134a are simply referring to a faulty or leaking R12 system; as such, the new system will appear to ‘blow colder’ after being overhauled.
  • Converting to R134a will not solve this problem any more than restoring your R12 system to its original condition will.
  • This is essentially a side-by-side comparison of a reliable R12 system and an R134a conversion system.
  • Seals and connections must be tighter as a result, and maintenance must be performed more frequently.
  • 2.
  • The newly introduced PAG oil may ultimately convert into a gelatin-like material if the R12 is not completely flushed out of the system during the conversion.
  • 3.

In some cases, such as when doing a conversion, some backyard mechanics or shady establishments cut corners and do not replace all of the seals. PAG oil does not conform to the specifications of R12 seals, resulting in a significant reduction in the life of the seals as well as leakage.


This has been highly promoted in the past (and continues to do so) since it is better for the environment than using regular gasoline in your old automobile. In contrast to R12, it does not deplete the ozone layer. However, the true reason people do it is because it is less expensive and more convenient. R12 is pricey and difficult to come by, costing upwards of $50 a can. A 609 EPA license is also required before you can purchase any, requiring non-licensed owners to bring their cars to a licensed shop for service (going against the satisfaction of servicing their old car by themselves).

  1. You can see why most individuals aren’t hesitant to convert their automobiles when you consider the fact that R134a conversion kits are quite affordable.
  2. Restoration of vehicles to factory original condition (including original A/C systems) has surged in popularity, and many vintage restoration companies are acquiring, restoring, and maintaining both R12 automobiles as well as R12 recovery equipment to meet the growing demand.
  3. However, once you have a properly functioning R12 system, it will require less maintenance than a ‘converted’ R134a system, and it will also blow colder, reach temperature faster, and retain the originality of the car.
  4. Do your homework to determine whether or not switching to R134a is the best solution for you.


Is your R134a system not producing as much cold air as it should be producing? Do you think it’s just a matter of topping it off? Is it possible that you will just go to the auto parts store and get an A/C recharge kit? Hold on to it for a minute! Discover the reasons why you should avoid using a DIY recharge kit to maintain the air conditioning system in your automobile!


Andre Clemente is the founder of New Old Cars, LLC, which is licensed by the Environmental Protection Agency (EPA) (Mobile Vehicle Air Conditioning) The most recent change to this article was made on July 26, 2020.

Additional Article Sources:

Tim Gilles is a writer and poet. 4th Edition of the book Automotive Service: Inspection, Service, and Repair. Cengage Learning, 2012, Delmar, New Jersey. Print Brown, William L. – Union Carbide Corporation published a paper in 1998 titled ‘The Development of Lubricants for Automotive A/C Systems.’ .as well as many others! It is the NOC’s greatest delight to post only the most accurate information possible, which is obtained from reliable sources. Because some of the links are no longer live, not all of the sources are shown on this page.

NOC, on the other hand, downloads and preserves all of the sources that were utilized to support each and every point in this article.

All items on our website are subjected to this process, and NOC is pleased to make this information available to the general public. Our first objective is earning and maintaining your trust.


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