Hi, ALL!

I've been lurking for some time now, gaining valuable information about my new (to me) car. I've got a Euro 1985 e190 16 valve with yet another AC problem. The car was converted to R-134A two or three years ago. (Bad move from what I've read on your forum, but it wasn't my car then.) The compressor, clutch, and AC relay were changed out then, too. Don't think they changed out the dryer or any of the other temp/pressure switches or relays.

I replaced the AC relay because the old one looked like it had a bad rewire job. I also replaced the the aux fan relay--R3 in the fuse box. A mechanic friend who works mostly on Volvos replaced the expansion valve, cleaned out the system, and recharged it. Gauges read about 240 high and 30 low last time we checked about a month ago.

Symtoms:
AC in idle would start out nice and cold then the belt would chirp and the compressor would kick off and not come back on. Restarting the car recycles the compressor, but of course it just kicks off again. After I changed out the AC relay I took the car for a ride and everything seemed to be working. Drove the car to my friend's Volvo shop to check out the pressure in the system. As soon as the engine dropped down to idle the belt chirped and the compressor kicked off.

A Mercedes mechanic I know told me he thought it might be the belt tensioner or the compressor.

At highway speeds, the compressor continues to run without problems. The air is not super cool, but I'm guessing that may be a pressure problem. At any rate, I can't check out the temperature until I can keep the compressor running for awhile.

Any ideas? I'm very impressed with what I'm reading so far on this forum. I already know (thanks to Tinker) that the squeak in my rear end is a bushing in the left carrier (hub). I also am learning that I need at some point to change the timing chain tensioner --although the last owner changed the timing chain and said the tensioner looked fine. My car has 130.000 miles on it.

Thanks for the help in advance.

Dr. Skip

Adjust the belt tention and if it will not tighten to the correct tention replace the the belt tentioner. The Mercedes that uses 1 belt (Serpentine belt) has a rpm sensor in the compressor that shuts it down when the belt slips.

Thanks, Stan:

I'll try tightening it, but shouldn't the compressor kick back on after a bit? or does the rpm sensor keep it off line as soon at it senses a problem with the belt? By the way, the belt doesn't feel too loose to me. According to the records I have, the belt was replaced about three or four years ago at 119,000.

Skip

Two hours later:

I tried tightening the tensioner. Tensioner tightens nicely but the AC still doesn't work. Chirped a couple of times and stopped blowing cool air. I'm still stumped.

This can't be that difficult!