The compressor is one of the three main components to an air conditioner, as is compresses the refrigerant in the system. It is possible to replace the compressor by itself on your Chevrolet Astro van. You will, however, need professional help in preparing the van for this service due to the environmental hazards.
Take the van to a shop where he air conditioning system can be discharged. This step must never be attempted by anyone but a professional due to the pressure the system is under and the laws regarding air conditioning refrigerant.
Disconnect the negative (black) cable from the battery.
Loosen the engine cover's upper retaining screws from the engine compartment firewall (you can't completely remove the screws). Move the front seats all the way back and remove the instrument panel's lower extension by removing its retaining bolts with a wrench, pulling it away from the cover and unplugging the electrical connectors. Unlock the two latches for the bottom of the engine cover and remove the cover.
Detach the wire harness and ground wire to the compressor so you can remove the drive belt, along with the air cleaner and the engine air intake duct. Remove the drive belt by loosening the tensioner with a breaker bar or ratchet and removing the belt with the pulleys. Remove the oil filter tube if the Astro is a 1996 model or later.
Unbolt the refrigerator hose manifold from the compressor with a wrench; the bolt is at the rear of the compressor. Cap all the fittings with small caps or rubber plugs.
Remove the mounting bolts at both the front and back of the compressor and remove it from the vehicle.
Install the new compressor in place on the air conditioner unit and fasten the bolts. Connect all necessary parts like the refrigerant hose manifold.
Re-install all other parts like the oil filter tube and drive belt in the reverse order of removal. Adjust the drive belt as needed by loosening the adjusting and pivot bolts on one drive belt component and moving that component away from the engine to tighten it or toward the engine to loosen it.
Take the van back to the same shop as before to have the air conditioning system evacuated and recharged.
