AC Compressor Cycling on and Off

Post by **mtd240** » 19 May 2012, 13:56

So, the AC on my '96 850 doesn't work. I bought some R134a, and pumped it up, and now the compressor cycles (every 3-4 seconds). It didn't even turn on before. I suppose that is a good thing.

The pressure is up at ~90 when the compressor is off. When the AC is on, the pressure goes up to 45, then the clutch disengages and the pressure drops to 25. It continues to do this over and over - what is the problem?

Sorry for the ignorance - I just want working AC

Mike

jonesboy1983 · Post by **jonesboy1983** » 19 May 2012, 14:12

You need another can of R134a. Yours was so empty that the first can just got it to cycle. Now another can should get it to stay on.

Post by **mtd240** » 21 May 2012, 08:25

Thanks - you were right. The can I had wouldn't push anymore refrigerant in past the 100 psi static pressure (seems kind of large?), but turning the car on and getting the compressor running moved that pressure down enough to let me push some more R134a in there

Thanks again - might want to just delete this thread, mods, considering you have a stickied AC section at the top of the page.

Mike

Post by **jblackburn** » 21 May 2012, 08:31

The compressor always needs to be running for at least 2-3 minutes before you try to load up the system. Charge it up until the compressor quits cycling with the engine idle held at ~1500-2000 RPM.

In all likelihood, this thing has a rather large hole in the system somewhere (99% of them have had or currently have a hole in the evaporator core) and will need to be recharged during the course of the summer.

cambiecbc · Post by **cambiecbc** » 08 Jun 2013, 18:41

The A/C worked whole last summer after fixing the clutch gap and refill coolant. There was warm air coming out from the vents with AC on.
Try several times to refill coolant with steps same as the above post by iblackburn. The compressor ran same as 1st posted by mtd240. The static pressure was 55psi when A/C was off. The copper parts of the refill kit didn't fill cool during the filling.
It seems that the coolant didn't enter the system even the tape open fully wide.
Any other problems not observed?
Thx

Post by **abscate** » 08 Jun 2013, 19:50

Pressure measurements on AC systems are meaningless unless the System is equilibrated and ambient temperature is noted. If you are adding two cans if freon to a system you have a problem that needs to be fixed. The freon will not displace air in the system, so using the leak sealer will probably not help as it will harden throughout the system, not at the leak.

The evaporator core is the most likely culprit.