Mechanics

Air Conditioner Compressor Replacement

Step by step instructions on how to replace an automotive air conditioner compressor. This repair guide pertains to all cars.

Difficulty Scale: 4 of 10

Tools and Supplies Needed

  • Air conditioner compressor
  • 134a refrigerant
  • Recharge Kit
  • Compressor oil
  • Wrench set
  • Socket set
  • Shop towels
  • Safety eyewear and clothing
Before you begin work, park your car on a flat surface with the emergency brake on. Engine must be cold.

Step 1 - Remove the negative cable from the battery. (Note: Before disconnecting the battery, make sure you have written down radio presets. They will need to be re-entered after the battery is reconnected.)

Step 2 - Next, locate and connect charge hose and valve to the high or low pressure service port to the recovery station. A small amount of refrigerant oil will be removed along with the refrigerant, make sure to replace the same amount of oil before recharging the system. Refrigerant oil is susceptible to moisture contamination so be sure to use only new refrigerant oil. In severe conditions, when a machine is not available refrigerant can be slowly released into the atmosphere via the charge port, 134a is not an environmental hazard such as r12.


Compressor High Pressure Side Port

Step 3 - Once the system has been vacuumed by the refrigerant recovery machine remove the serpentine belt, covers or accessories like a alternator to gain access to the compressor if needed. (Note: Check the condition of the serpentine belt and replace if necessary.)

Step 4 - Next, remove electrical connector to the compressor.

Step 5 - Then. remove hose set for the compressor. (Note: sometimes there can residual pressure in the system which release for a short time, this is normal.)

Step 6 - Now, remove the air conditioning compressor mounting bolts and remove the compressor. (Note: Oil is in the compressor, care should be given when removing.)

Step 7 - Compare the old and replacement compressor to make sure they are identical.

Step 8 - Install the replacement compressor and tighten all bolts.

Step 9 -  Before re-connecting the high and low pressure hoses be sure to replace the sealing o-rings with new. Install a small amount of refrigerant oil on the o-rings prior to installation. Connect the high and low pressure fittings to the compressor.

Step 10 - Re-connect battery.

Step 11 - Before re-charging the system make sure to evacuate the system completely. Check the refrigerant capacity to make sure you do not over fill the system, too much refrigerant can hurt cooling efficiency as much as having too little refrigerant can. If the vacuum reading isn't more than 93.3 kPa or 10 inches in 15 minutes, there is more than likely a leak somewhere in the system. Only recharge using the low side pressure fitting. Once a leak is located you will need to evacuate the system before attempting to repair it.

Step 12 - To re-charge AC system please VISIT - Air Conditioner Recharge


Helpful Information

Before attempting to replace an air conditioning compressor there is refrigerant inside the air conditioning system is under high pressure and should not be released directly into the atmosphere. The refrigerant is expensive and recyclable. Recovery of the refrigerant should be done with a recovery/recycling/charging station. Once finished with the compressor replacement, you can re-use the old refrigerant using the same charging station.


AC Refrigerant Recovery Machine

Best Practices

  • When charging the system be sure to replace the same amount of oil that was removed during the refrigerant recovery process.
  • Charge system with the manufacturers recommended amount of refrigerant.
  • Use refrigerant leak detector to make sure no refrigerant leaks are present.
  • If the air conditioner is weak or not working at all follow this link to repair- Air Conditioner Not Working
 

AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2013-11-14)