How to Replace the AC Compressor in Vehicles

by Contributing Writer

The air conditioning compressor is one of the main components in your Vehicles AC system. One of the key signs of a compressor that needs to be replaced is a loud buzzing sound. Because of its high pressure and environmental regulations involving freon refrigerant, you need to use extreme caution when replacing this or working on any other component of the air conditioning system. It's a good idea to talk with an automotive air conditioning technician about specific details on how the compressor is connected and the type of refrigerant used.

Under The Hood:

 How to Replace the AC Compressor in a Pontiac Firebird

Removal

Take your Firebird to an automotive repair shop that has a licensed air conditioning technician who can properly discharge the refrigerant according to EPA regulations.

Disconnect the car's battery by loosening and removing the negative cable with an insulated wrench.

Rotate the drive belt tensioner, typically located on the smallest pulley, clockwise with a ratchet and socket then slip the belt off its pulleys. Slowly release the tensioner and remember the exact pattern the belt followed. (The belt routing diagram is located on the radiator support; if it's missing, sketch the routing before removing the belt.)

Raise the car with a jack and support it on jack stands.

Clean off all the fittings for the refrigerant lines at the compressor--the canister-like device on the air conditioner with the drive belt pulley on it--with shop rags then disconnect the fittings with a wrench along with the electrical connector for the compressor.

Remove the bolts for the compressor's front bracket with the wrench then lower the compressor from the engine.

Pour the refrigerant oil from the compressor into a graduated container to measure its amount.

Installation

Pour fresh refrigerant oil--the same amount used in the old compressor--into the replacement compressor.

Install the compressor into its bracket and tighten the bolts with the wrench.

Reconnect the refrigerant lines and electrical connector, using a new seal on the refrigerant line fitting lubricated with refrigerant oil.

Lower the car from the jack stands with the jack and reinstall the drive belt onto its pulleys using the tensioner. Refer to the diagram on the radiator support or your sketch to make sure you route the belt along the correct path.

Reconnect the battery cable and take the Firebird to the automotive shop to have its AC system evacuated and recharged.

Items you will need

  • Insulated wrench

  • Ratchet and socket

  • Floor jack

  • Jack stands

  • Shop rags

  • Graduated container

  • Refrigerant oil

  • Replacement AC compressor

  • Refrigerant line connector seals

 How to Replace the A/C Compressor in a 1998 LeSabre

Removing the Old Compressor

Have the R-134a refrigerant removed from the LeSabre's A/C system by a trained service technician before starting work. Most repair shops have the expertise and the equipment to safely reclaim and store the refrigerant from the vehicle. Do not release refrigerant into the air.

Park the LeSabre on a flat, level surface. Open the hood and disconnect the negative terminal cable from the battery.

Locate the belt routing diagram near the front of the vehicle. If the diagram is not available, refer to the owner's manual for the proper belt routing procedure. Place a socket wrench with a breaker bar on the belt tensioner on the passenger side of the engine and move it counterclockwise to relieve tension from the belt. Slide the belt off the tensioner and the other remaining pulleys. Slowly move the tensioner back into position.

Loosen the wheel lugs on the front passenger side wheel with a lug wrench. Raise the front of the vehicle with a floor jack and secure the vehicle with jack stands. Finish removing the wheel lugs and dismount the wheel from the hub.

Pry away the plastic pins with a slotted screwdriver to remove the plastic wheel well splash guard. Unbolt the bottom plastic cover underneath the front end of the vehicle with a socket wrench.

Follow the A/C system plumbing toward the rear of the compressor. Remove the bolt holding the plumbing to the compressor and move it out of the way. Locate the electrical harness near the compressor clutch and unplug it. Loosen the three bolts holding the compressor to its bracket with the socket wrench.

Remove the bolts while holding the compressor in place and carefully guide it out of the vehicle. Drain the compressor of oil by holding the rear of the compressor over a measuring container while rotating the clutch by hand in the direction of rotation during normal operation.

Installing the New Compressor

Observe how much of the old oil you drained in the measuring container. Pour the same amount of fresh compressor oil into another measuring container. Add that amount of oil into the compressor through the compressor's intake port at the rear while turning the clutch in the direction of rotation during normal operation.

Mount the new compressor to the bracket and insert the three retaining bolts while holding the compressor in place. Tighten the bolts with the socket wrench.

Reinstall the plumbing to the rear of the compressor and reinsert the retaining bolt that holds it in place. Tighten the bolt with the socket wrench.

Reattach the plastic splash guard to the wheel well. Reattach the bottom plastic cover to the front of the vehicle. Mount the wheel onto the hub and hand-tighten the wheel lugs. Remove the jack stands and lower the vehicle to the ground. Torque the wheel lugs to 100 foot-pounds with a torque wrench.

Route the belt around the pulleys according to the belt routing diagram. Move the tensioner counter-clockwise and slip the belt onto the tensioner. Slowly move the tensioner back into position.

Make sure the belt is lined up properly on all of the pulleys. Reconnect the negative terminal cable to the battery and close the hood.

Have a trained service technician purge the A/C system of trapped air and add both additional compressor oil and R-134a refrigerant. Discard the old compressor oil in an environmentally friendly manner.

Items you will need

  • Socket wrench

  • Breaker bar

  • Floor jack

  • Jack stands

  • Slotted screwdriver

  • Measuring containers

  • PAG compressor oil

  • Torque wrench

 How to Replace the A/C Compressor in a Honda Accord

Evacuate the A/C system with certified collection equipment by taking your Honda Accord to a garage or oil-change facility. Most garages will evacuate the system for free, as they are paid according to how much Freon they collect. The system must be evacuated and depressurized with professional equipment.

Disconnect the battery by turning the positive terminal bolt in a counterclockwise direction. Set the terminal aside, so that it does not touch metal.

Remove the drive belt from the compression pulley. Press firmly onto the tension pulley to get enough slack to work the primary drive belt off the idle pulley at the top of the motor. Let go of the tension pulley, and the belt should now have enough slack to be removed from the compressor pulley wheel. Slide it from the grooved pulley carefully.

Disconnect the wiring harness adapter by pulling it free of the compressor terminal.

Remove the line bolts that connect the Freon exchange lines to the compressor by turning their hexagonal ends counterclockwise. Some latent hissing may occur from the evacuation, but it should not be sustained or dangerous.

Remove the compressor by turning the mount bolts counterclockwise, sliding the bolts out of the mount arms, then working the compressor free.

Replace the compressor with a new unit by positioning it into the mount arms, then sliding the mount bolts back into place. Turn the mount bolts clockwise until snug.

Plug the wiring harness back into the compressor by pressing the adapter plug onto the compressor terminal.

Restore the exchange lines by turning their line nuts clockwise into the correct openings on the compressor. Replace the gasket on the end of each line if necessary.

Secure the drive belt over the A/C compressor pulley wheel, then press the tension pulley firmly to slide the belt underneath the idle pulley. Release the tension pulley and the belt will tighten.

Replace the battery terminal by turning the positive terminal bolt clockwise until snug.

Refill the system with Freon by plugging the female adapter tip on the Freon fill valve into the male adapter on the evaporator line. The valves available will allow only the correct connection; don't force the valve nozzle onto the wrong nipple. Run the A/C with the can of Freon connected, and the system will draw the coolant into the lines. Your Honda Accord will take in about 1.6 pounds of 134a coolant.

Items you will need

  • Socket set

  • Screwdrivers

  • Freon fill valve (gauge recommended)

 How to Replace the AC Compressor on a Subaru Forester

Remove all freon from the air conditioning system by evacuating it with professional equipment. Most garages and oil change facilities will evacuate the freon for free, as they get compensated for collecting it. Never vent the system into the atmosphere, because it could harm the environment.

Disconnect the power system by turning the battery's positive terminal bolt counterclockwise. Set the loose terminal wire aside.

Remove the freon coolant lines by turning the line nuts at the compressor counterclockwise, then pulling them from the openings. Check the gaskets in the line nuts for cracking or corrosion.

Press the tension pulley arm firmly to slide the primary drive belt out from underneath the idle pulley, then release the tension pulley arm. The belt will slacken enough to remove it from the compressor pulley wheel.

Remove the compressor by disconnecting it from the wiring harness (pull the adapter plug from the terminal) and turning the compressor mount bolts counterclockwise. Slide the bolts out of the mount arms, and pull the compressor out of the Forester.

Replace the compressor by positioning it into the mounts and sliding the bolts into place. Turn the bolts clockwise, then connect the adapter plug to the terminal. Reattach the freon lines by turning the line nuts clockwise into the openings on the compressor.

Wrap the drive belt around the compressor pulley wheel, groove side down. Press the tension pulley arm and slide the belt underneath the idle pulley, then release the tension pulley arm. The belt will tighten around the engine components. Reconnect the positive terminal bolt on the battery to restore power to the vehicle.

Refill the system with freon by using a home kit, or take the vehicle to the same shop that evacuated the system in order to have it refilled. Freon does not get "used up," so freon can be recycled. It is not recommended that a home kit be used, even though it may be cheaper, because the equipment tends to be cheap and unsafe.

Items you will need

  • Socket set

  • Line wrench

 How to Replace the AC Compressor in a 1989 Chevy Truck

Drive the vehicle to a facility licensed in air conditioning and have them evacuate the system.

Unplug the wiring harness connector for the air compressor. Rotate the accessory belt tensioner toward the engine to loosen the belt. Lift it off the air compressor pulley, but leave it on the rest of the pulleys.

Remove the compressor brace, if your truck is equipped with one, using the appropriate socket. Remove the bolt from the center of the manifold on the back of the compressor. The manifold holds the high- and low-pressure lines onto the compressor. Pull the manifold and lines away from the compressor. Block the lines with a clean shop rag.

Remove the compressor mounting bolts, then lift the compressor out of the engine compartment. Most auto-parts stores charge a "core fee" for air compressors. If you return the old compressor, your core fee will be refunded. Remove the drier or accumulator and the orifice tube and replace both with new parts.

Pour the proper amount of oil into the air compressor. The instructions with your brand compressor will tell you how much oil to add. Put the plug back into the compressor and set the compressor up on its pulley for 20 minutes, to allow the oil to thoroughly soak the seals.

Install the air compressor and tighten the retaining bolts to 37 foot-pounds of torque. Remove the rags from the lines and the plugs from the compressor openings. Install the manifold and lines onto the back of the compressor. Tighten the manifold bolt to 24 foot-pounds of torque. Reinstall the compressor brace. Plug in the compressor wiring harness connector.

Rotate the serpentine belt pulley toward the center of the engine and slide the belt over the air compressor pulley. Allow the tensioner to rotate gently back in place. Take the vehicle to a certified air conditioning shop and have them charge the system.

Items you will need

  • Set of sockets

  • Clean shop rag

  • Torque wrench

 How to Replace the A/C Compressor on a Miata

Evacuate the air conditioning system by taking the Miata to a garage or oil change facility. They have professional recapturing equipment and get compensated for collecting freon.

Disconnect the battery by turning the positive terminal in a counterclockwise direction. Store the terminal away from metal.

Press the tension pulley arm until there is enough slack to slide the belt out from underneath the idle pulley. Release the tension pulley arm and the slack belt should come off of the compressor pulley wheel easily.

Disconnect the freon lines by turning the line nuts counterclockwise. Store the lines away from the compressor.

Remove the compressor by turning the mount nuts counterclockwise while holding the bolt heads with a socket wrench. Disconnect the compressor from the wiring harness by pulling the adapter plug from the compressor terminal. Slide the mount bolts out of the compressor mounts, and the compressor can be manipulated out of the engine bay.

Replace the compressor by positioning it into the mount arms, then sliding the mount bolts into place. Secure the mount nuts by holding the bolt heads and turning the nuts clockwise. Reattach the wiring harness adapter plug to the terminal.

Attach the freon lines to the compressor by turning the line nuts in a clockwise direction until they are tight. Wrap the belt around the compressor pulley wheel, groove side down. Press the tension pulley and slide the belt underneath the idle pulley, then release the tension pulley arm. The belt will tighten around the compressor.

Reconnect the battery by turning the positive terminal bolts in a clockwise direction.

Refill the system with an at-home kit or by taking the vehicle back to the garage to reclaim the freon that was evacuated.

Items you will need

  • Socket set

  • Screwdriver

  • Line wrench

 How to Replace an AC Compressor in a Dodge Caravan

Removal

Have the air conditioner system discharged and the refrigerant recovered. This should only be done by a qualified technician licensed to work on automotive air conditioners.

Disconnect the battery's negative cable by removing the air filter housing and then loosening the clamp nut for the cable.

Remove the drivebelt from the engine by turning the tensioner pulley lug with a wrench--clockwise on four-cylinder engines, counterclockwise on V-6 engines--slipping the belt off the pulleys and slowly releasing the tensioner. On four-cylinder engines, you also need to remove the power steering belt by loosening the bolts for the power steering pump and adjuster.

Disconnect the electrical connector (four-cylinder engines) or the wiring harness connector (V-6 engines) from the compressor clutch. On V-6 models, you also need to unscrew and remove the bracket on top of the compressor.

Detach the refrigerant lines from the compressor and plug them with rubber plugs to prevent contaminants from getting in.

Remove the compressor's mounting fasteners--there should be five that require a wrench--and lift the compressor out of the vehicle.

Installation

Add fresh refrigerant oil to the new compressor, making sure you have the correct type for your vehicle and compressor. Pour the oil from the old compressor into a graduated container to find out how much oil you need for the new compressor.

Install the new compressor in place in the engine and apply the mounting bolts.

Connect the refrigerant lines to the new compressor. Remove the plugs from the lines and install new O-rings, lightly coated with refrigerant oil, onto the line fittings before connecting them to the compressor.

Re-install and connect the wire harness, drive belts and battery cable in reverse order of removal. For the drive belts, route them in the same path they originally were in and make sure they are centered on the pulleys.

Have the air conditioner system evacuated, recharged and tested for leaks by the same technician that discharged the system.

Items you will need

  • Wrench

  • Screwdriver

  • Rubber plugs

  • Compressor

  • Refrigerant oil

  • Graduated container