My A/C worked in my car for about a month after I bought it (1/03) and eversince then it hasnt worked. My uncle looked at it once and got no pressure from the A/C compressor. I know it should be converted, but do I need to buy a whole new A/C compressor? If not that, how would I fix this?

 

it could be one of 2 things...

1) the compressor is fried, but, you would hear that more than likely

2) the compressor clutch has failed.

determine which has occured and go from there.

 

You can verify the charge is gone by depressing the schrader on the Accumulator. If nothing comes out, you can be pretty sure it leaked out. You can verify the compressor works by turning on the a/c and then using a paperclip, momentarily jumper the harness to the lower pressure switch. If the a/c compressor comes on, it at least works. Before converting, you should try to find the leak; otherwise all the new stuff is going to leak out too. Check for a/c oil on the hood above the compressor. If it's there, the shaft seal is shot and you can either replace it with a kit from Napa or buy a new compressor. Before starting, get rid of any remaining charge, replace the accumulator and if it was leaking, you should probably replace the orifice as it is more than likely filled with debris. Use a synthetic a/c oil as the typical R134 oil (PAG) is incompatible with the mineral oil used with the old charge. Put at least 4 ounces of oil in the new accumulator and probably another 2 ounces in the flexible hose from the accumulator to the compressor (capacity is 8 ozs, but unless you're flushing the old oil out, some of it's going to remain). If you replace the compressor put 4 in the accumulator and 4 in the compressor. A vacuum needs to be pulled to get the moisture out and to suck in the first can of the new charge. Charge to 80% capacity (2.25lbs or 36ozs for most Vettes so two 12 oz cans and a tad more should be sufficient). Turn the low pressure switch adjustment screw (between the terminals) a 1/4 turn counterclockwise or until the system cycles off at about 22 psi.

 

Who needs A/C? Rip it out, weight reduction! :D

Kidding...

 

SunCr gave you a lot of good information. I would add to that a couple of things.

- If you've got access to a compressor, blow out the old mineral oil. It won't hurt anything if you leave it in there, but (at a minimum) it takes up volume and may lower the efficiency a little. Since R134a won't work as well as the R12, you want to do everything you can to optimize it. Also, if you blow out the system, capture the residue in a rag and look for any particulates (espacially black stuff). If you find anything you'll have to blow out/flush the entire system. When I did this a few years ago I bought a flushing/cleaning liquid for car A/C systems from PepBoys.

- You have to make sure that you've fixed all the leaks. Since the oil circulates in suspension with the freon, when the freon leaks out, the oil leaks out with it. I suspect that a lot of people don't realize this and just add freon. After a while the compressor runs dry and self-destructs.

-If you're system is already vented, then consider replacing all the o-rings/gasket seals with the newer, R134a compatible versions.

Good luck


[Modified by sraft, 12:47 PM 12/24/2003]