a/c not working

[schumi]

Hi all. The a/c on my '87 300E stopped working a few weeks ago. Not working at all, nada, after working great. I am a reasonably competent backyard mechanic (have changed shocks, springs, fluids, plugs/wires, but nothing major) but have never done any a/c troubleshooting of any kind. I'm not even sure how to tell if the compressor clutch is engaging. Can someone give me some pointers so I can try to narrow the problem - I want to have an idea of what is going on so I don't get ripped off by a shop doing any unnecessary work, even if I can't fix it myself. Thanks.

[y2kimmel]

Get a refrigerant charge from an A/C shop - and ask them to include leak testing dye in the charge.

If they tell you that the car is fully charged already - then it's likely a mechanical or electrical problem (compressor, clutch, relay, A/C board, etc.)

If not - then you probably have a leak. When the system loses its charge, take it back to the shop and they can check to see where the leak came from - pinpointing your problem.

Hope this helps. I'm doing this same process right now. I fear that my leak is from the evaporator. There go the vacation savings!

Troy
1995 e420

To see if the compressor is engaging, simply look at it with the engine running while someone turns on the a/c with engine running. The very forward portion in front of the pulley will not be turning with a/c off. When a/c is turned on it should turn.

If it is turning, see if the blower is running. If the blower is not running, you need to troubleshoot the blower. If it is blowing HOT air all the time, and I mean HOT, not just not cool air, then the heater valve is being turned on and you will need to troubleshoot the ACC to see why the heater valve is on all the time.

Hope this helps,