How to Fix a Car with an Air Conditioning Leak

By | April 5, 2022

How to Fix a Car with an Air Conditioning Leak
If your car has an air conditioner refrigerant leak, it can be fixed by a home DIY (do-it-yourself) backyard mechanic.

There are a few ways to approach a leaking air conditioning system.

If the leak is slow, it likely is small, and a can of Stop Leak can be added to a system to help it seal up.

If the leak is large, it will need to be fixed and the A/C system set into a vacuum before adding in refrigerant.

Below is how both methods can be done to fix a vehicle A/C system.

How to Fix a Car Air Conditioner with a Small Slow Leak

There is a stop leak that can be added to see if it seals up an A/C system.

I have used it successfully many times, and it works well as long as the leak is not too big.
How to Fix a Car with an Air Conditioning Leak Stop Leak
An A/C system with a small leak will slowly stop working, while a big leak will stop all at once.

Using Stop Leak is low-cost, quick and easy, making it a good method if the leak is small enough.

The stop leak is mixed with refrigerant and simply added to a system on the low pressure line (Big-Line).

A hose is used along with a can of Refrigerant Stop Leak, which is quick and easy to do.

Tools and Parts Needed to Fix a Large Leak

  • Gauges
  • Vacuum Pump
  • Refrigerant

If the stop leak does not work, the leak will need to be fixed by replacing the bad part.

Some tools will be needed, but there are inexpensive budget options and loaner tools from auto part stores.

If you only will be working on a single car, many auto parts stores such as Auto Zone will loan out gauges and a vacuum pump for a deposit.

There are also many good budget tools on Amazon that are a good option, especially if more than one car will be fixed.

Refrigerant will also be needed to refill the system.

The most common refrigerant used in cars and trucks is R134a. Of course, check to be sure.
How to Fix a Car with an Air Conditioning Leak Refergeant Type
Most cars and trucks have a label under the hood somewhere.

How to Fix a Car Air Conditioner with a Large Leak

  1. Find the Leak
  2. How to Fix a Car with an Air Conditioning Leak Oil Spot
    The first step is to find where the leak is. Since refrigerant is oily, look for any spots on the A/C hoses and compressor.

    The hoses are a very common source of a leak.

  3. Fix the Leak

  4. The leaking part will need to be replaced, such as a hose.

  5. Vacuum Down the System

  6. All air conditioning systems need to be in a vacuum before adding refrigerant into the system.

    This also helps to find any leak since the vacuum will not hold if there is still a leak.

  7. Add Refrigerant
  8. Once the leak has been fixed and the system is in, a vacuum refrigerant can be added back in.

    The correct amount of refrigerant needs to be added back in, or the A/C will not work.

    Overfilling a system with too much can damage parts.

    There is two ways to add back in the correct amount of refrigerant.

    Use the gauges and add refrigerant to the correct pressure.

    Use a scale and add in the correct amount by weight.

    All vehicles will have a pressure they operate at which can be looked up and set at.

    A/C system will also have the amount in pounds that can be added into a system using a scale.

    Whichever way is used refrigerant will need to be added back into the system.

Fixing a leaking car air conditioning system falls in the do-it-yourself category.

Many leaks can be fixed with a can of refrigerant stop leak and a hose to add it into the system.

For larger leaks the bad component will need to be replaced and refrigerant added back in.

If you have a very hard-to-find leak, a dye can be added to the A/C system, which helps to see where it is leaking.

There are also refrigerant leak detectors that can sniff out a leak and beep loudly as it approaches a leaking spot.

Using a low-cost leak detector is the best option as they are quick and easy to use.

Bob Thomas
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