190shadetree

'88 190E 2.3 8v

My A/C compressor shuts off at around 95 degrees, most of the time. It will not come back on until the temp gauge drops.

However, lately, it has been shutting off at cooler temps - under 80 degrees. Tonight, driving home after dusk, the A/C stayed on all the way home, pumping cold air, even with the temp gauge above 95. But, I'm sure tomorrow, in the hot humid weather, it will shut off again at 95. It always does.

I won't swear to it, but I think my A/C pressure is fine. I had an R134 conversion last year including a new A/C manifold, and when the compressor is on, I have ice cold air.

I replaced the "A/C ACC emergency shut off sensor" (the two prong sensor in the intake manifold, up close to the distributor and blue in color). No change.

I'm at wits end. This has got to be something simple, but I haven't found it.

Any ideas apppreciated.

mctwin2kman

Probably either too much pressure on the high side, since pressure will increase with temp. Or it could be a bad pressure switch on the high side as well. What I would do is attempt to release some pressure from the high side and see if that helps, since you can go to the local parts store and buy a re-fill touch up bottle of R134a for 10 bucks or so. Mine would not cycle properly as well. My father in law and I were looking at it and accidentally let pressure out when were were looking at the high side fitting. We let out quite a bit and then like magic the compressor shot to life again. So I bought about 2 cans of the re-fill stuff and used one full one so far and she is nice and cold again. Of course it only works when I hit the Max AC button in my 1986, but oh well. I am still wondering why the compressor does not cycle on the regular AC setting.....

190shadetree

Stupid question: Which side is the high side? I see a fitting in the radiator area and another up on the firewall by the shock tower.

mctwin2kman

The red is high, in front of raditor, the low is blue and is by the shock tower on the drivers side.

190shadetree

Well, now the compressor kicks off very early - before the engine even warms up to 80 degrees. I picked up a recharge kit at Walmart tonight. The gauge reads "filled" at idle, but "recharge" at 1500rpm or so. I added a can of r134a and it now reads "filled" at all speeds with little fluctuation between idle and 1500rpm.

Tomorrow's gonna be another steamer - 90+ degrees. I'll report back if the problem is fixed.

190shadetree

That's a negative, Houston.

A can of r134a did nothing. Next trip out it still cut out by 80 degrees. Trip after that, it cut out within 2 minutes of leaving home. This afternoon, it worked fine for a short, 10 minute drive home.

I would really appreciate any more pointers on what to check. This thing is driving me nuts and it's hotter than hell in the car in the afternoon.