AC Compressor Replacement Instructions

by Jeffrey Caldwell

The nightmare of every driver and passenger is being caught inside a vehicle on a hot summer day when the air-conditioning compressor breaks. Many modern vans and SUVs are not designed to have their rear windows roll completely down, so riding inside can feel like being trapped inside an oven. Automotive systems can be service by the home mechanic, but you will need the assistance of a certified AC technician.

Before You Begin

AC control panel in a Volkswagen Jetta

Automotive air-conditioning systems utilize a toxic refrigerant that if released into the atmosphere can be an environmental hazard. It is illegal in the United States to release automotive refrigerant into the air. Therefore, before you begin any service or repair, you must have the air-conditioning system evacuated by a certified technician and have the refrigerant recycled.


Serpentine belt drive system in a Volkswagen Jetta

Begin by disconnecting the ground cable from the negative battery terminal. Locate the air-conditioner compressor---it will usually be mounted somewhere on the side of the engine. Loosen the accessory drive belt and remove it. Label and disconnect all of the electrical connections from the compressor. Disconnect the refrigerant hose manifold from the back of the compressor and plug the hoses to prevent dirt, water or grease from entering the lines. Loosen the bolts that connect the compressor to the engine. Carefully study how the compressor is mounted and remove the hardest to reach bolts first. Lift the compressor out of the engine bay.


Before you begin installing the compressor, you must fill it with AC compressor oil. The amount of oil you need to add will be listed in the vehicle's service manual. Position the compressor in the engine bay and reinstall the bolts that connect it to the engine. Unplug the refrigerant lines and reinstall the refrigerant hose manifold. Reinstall all electrical connectors following the labels you made previously. Reinstall the accessory drive belt and adjust the tension. Depending on the design of your vehicle, this will be accomplished either by loosening the mounting bolts on the compressor and pulling it away from the engine or by adjusting a separate tensioning pulley. Last, reconnect the ground cable to the negative battery terminal.

Test and Recharge

The last step in the process must be completed by a certified air-conditioning repair technician. He will be able to test the system for you and recharge the system with new refrigerant.


About the Author

Jeffrey Caldwell has been a freelance writer for over five months and has published over 250 articles on websites like eHow and Caldwell writes articles on a wide range of topics including travel, camping and automotive mechanics. He has a Bachelor of Arts in English from Millersville University.

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