If you need to carry out major repairs to your car's air conditioning system, such as fitting a new compressor, evaporator or condenser, you can take the opportunity to add some new refrigerant as well. Follow the instructions in this article to update the machine system with a new refrigerant, such as R134a.
Steps
Part 1 of 3: Prepare the System for the New Coolant
Step 1. Make sure you have aspirated all the old liquid from the air conditioning system
It is best that this is done by a mechanic, both for safety reasons and to make sure that the refrigerant is disposed of according to the law. The mechanic knows the correct procedures for removing and disposing of this liquid.
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Ask him to remove any residual mineral oil. Make sure you rinse the system pipes with a solvent compatible with the R134a refrigerant.
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The mineral oil that is returned to the system must be of the same type as the drained one. If your car contained PAG oil, the mechanic should still use PAG oil.
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Step 2. Install a dry accumulator or receiving system that contains a desiccant
This substance removes the moisture that has accumulated in the air conditioning system.
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If the system has an accumulator, you should find it near the evaporator outlet.
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The dry receiving system is available on systems that use a lamination valve to control the flow of the refrigerant; it is connected to the pressure lines between the condenser and the lamination valve.
Retrofit Air Conditioning in Cars to New Refrigerant Step 2Bullet2 - Make sure the desiccant is compatible with R134a refrigerant.
Step 3. Replace the gaskets found at each joint
Proceed even if you believe it is not necessary, this way you do not have to do it later, in case they do not guarantee a perfect seal.
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When you remove an old gasket, tape it to a sheet of paper, note exactly where it was, and keep the sheet for a while.
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If you have a leak in a connection, take the gasket you installed, carefully checking that it is exactly identical in size and shape to the original one. Most air conditioning leaks are caused by poorly installed O-rings.
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Step 4. Inspect the pipes
Those conducting R-12 refrigerant should work as long as they are not cracked or damaged; if they are damaged, replace them.
Step 5. Install a high pressure circuit breaker if you don't have one or if you need to replace the old one
When the system reaches too high a pressure, the switch shuts down the compressor to prevent damage to the system and prevent refrigerant leaks.
Step 6. Check the tube with the calibrated orifice
You can find it connected to the high pressure side near the evaporator or on it. In some cases, it is mounted in the vent of the condenser; don't try to clean it, you have to change it.
Step 7. Add the correct PAG oil, if the mechanic didn't
Make sure the viscosity is the one recommended by the vehicle maintenance manual.
Part 2 of 3: Adding a New Refrigerant
Step 1. Connect the refill valve and service hose to the refrigerant can
Step 2. Open the valve on the pipe
This way you puncture the top of the can.
Step 3. Slowly turn the valve back to release some liquid into the tube
The refrigerant pushes the air out of the pipe so that it does not enter the air conditioning system.
Step 4. Close the valve to prevent liquid from escaping
Connect the other end of the service hose to the lower adapter on the implant.
Step 5. Hold the coolant can upright so that the system does not suck up its contents
Your goal is to let only the refrigerant vapors in.
Step 6. Connect the high pressure gauge to the upper service port
This tool allows you to verify that the recharge is proceeding accurately.
Step 7. Start the engine
Turn on the air conditioning system by setting it to maximum.
Step 8. Open the refrigerant valve and let the system suck in the vapors
Extraction takes about 10 minutes and the air coming out of the vents inside the passenger compartment gradually becomes colder.
Step 9. Check the pressure gauge
When it reaches a value between 15, 5 and 17 bar, close the valve on the refrigerant can. Remember to always close the valve before disconnecting the can, to avoid spraying the liquid into the atmosphere.
- Typically, the implant needs about 355ml of liquid.
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If the system is not fully charged even though you have used all the coolant in the can, you can add more until the gauge shows the above values.
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Part 3 of 3: Finishing the Job
Step 1. Store the coolant can with the service hose connected
This liquid does not degrade, so you can use what remains next time. Just be careful to store the container in a cool place, so you don't run the risk of overheating and exploding. You can also try to resell the substance to a collection center or certified technician.
Step 2. Install R134a adapters on the upper and lower service port
This way you avoid cross-contamination of the refrigerant, as well as being a legal requirement.
Advice
- If the system stops producing cold air after some time, it may have a leak. You can use a specific dye to identify the point from which the liquid comes out and then repair the crack with sealing products (if the system manages to maintain the vacuum for at least two weeks); alternatively, you can take the car to a mechanic (if the system fails to maintain a vacuum for two weeks).
- You can purchase a retrofit kit at your local auto parts store if you prefer not to buy the various parts individually on your own. Follow the instructions on the kit to upgrade the air conditioning system.
Warnings
- Be careful to keep your hands and tools away from very hot and moving mechanical parts of the engine.
- Wear protective gloves and goggles when working on the air conditioning system. If the coolant comes into contact with the skin, it can cause cold burns.
- Replacing the mineral oil in the air conditioning system on your own could void the warranty. Check the consequences you may face before doing maintenance without the help of a mechanic.
