This is on my 1997 Dodge Caravan.
About 3 weeks ago, whenever my A/C kicked on I heard the drive belt (V belt that only drives the compressor) squeal. I immediately think, aha loose belt, no prob.
I check the belt and it is tight, OK, it looks a little worn.
I get out the auto stethoscope and check all the bearings and find the serpentine belt tensioner bearing is not a happy camper but the compressor sounds fine while running and freewheeling both.
I pop down to the parts store and get a serpentine belt and an A/C belt and replace the bearing in the tensioner.
All seems well… Get on the freeway and the A/C kicks on, HUGE SQUEAL for 3 seconds and the car slows down, then the A/C is running and getting cool like nothing happened. :dubious:
The compressor starts cycling and every start is accompanied with a 1 second squeal and slowing of the car, but the system still cools. I try putting it in neutral and letting the engine idle while turning on the A/C compressor, no problem, all is fine.
It just doesn’t like being engaged at high RPMS.
First double check all the obvious stuff, Belt is not upside down or loose, it is the correct belt.
At home I try turning the compressor by hand, the front part (connected to the compressor shaft) turns easily, if I turn it fast enough, I can feel a little back pressure starting to build like it should.
I ran the ventilation computer through it’s calibration, it flipped all it’s vents, got cool and hot and all was happy.
Hung my A/C gauges on the system and the charge seemed fine, I didn’t check the temp to pressure ratio but it seemed normal enough, high side pressure when way up as I revved the engine however.
It is a 134a system.
At this point I am stumped, the system cools fine and compressor sounds OK internally but it doesn’t like being engaged at high RPMS, once engaged I can rev the engine back up without problems.
Change the compressor? expansion valve? Is there a pressure bypass inside the compressor to allow engagement under load, verify the charge more carefully with a thermometer on the expansion valve?
I have already Googled it to death and found several other people with the same problem, but no answers.
BTW, this is my first new thread, be gentle, I just wish it was about something more interesting and earthshaking.