Air conditioner Compressor cycling inconsistantly

Tiny
NODUMPING
  • MEMBER
  • 1997 FORD F-150
  • 4.2L
  • 6 CYL
  • RWD
  • MANUAL
  • 190,000 MILES
My air conditioner compressor began cycling on and off constantly yesterday, but not at consistent intervals maybe two seconds on, five seconds off, ten seconds on, two seconds off, you get the idea. It makes a loud noise when it cycles back on and also feels like it "jerks" the truck when driving (for lack of a better description) when cycling back on.

My number one suspicion is that the compressor is seizing up, and the noise and "jerking" when driving is because the belt is pulling so hard to try to turn the compressor. (Please excuse my lack of knowledge of all the proper terms for what I am trying to describe hopefully it is coming across one way or the other!)

However, a part of me is hoping it still may "just" be something in the clutch itself or the pulley, or something off in the pressure due to low coolant.

The pulley is free-spinning fine when nothing is turned on to cause the compressor to try to run.

All I had time to do last evening was use my father-in-law's low-side gauge only (I know, I know); and it did read low, and I added some Freon. No change in cycling problem, but I know I need both gauges and a real Freon level/pressure check.

This evening I will have time and tools to check low and high sides and remove belt to check clutch and pulley assembly more thoroughly, so I just wanted to ask for advice on what to check for?
Should I even check those things at all or go straight for the compressor?
I have seen some things about compressor bearings, but confess to a complete lack of knowledge there and have not had time for research yet. Any help on that?

Thanks so much for any help I can get!
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Thursday, August 11th, 2016 AT 8:33 AM

3 Replies

Tiny
HMAC300
  • EXPERT
It is supposed to cycle on and off if it does it more regular then it is probably low on Freon due to a leak or some other problem not necessarily the compressor and it cannot be done at idle it has to be checked at about 1500 rpm's. Unless both sides are checked. It may be compressor clutch needs adjustment or going bad or even a bad belt as those are recommended replacement for belt and tensioner at 60,000 miles.
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Thursday, August 11th, 2016 AT 9:39 AM
Tiny
NODUMPING
  • MEMBER
The belt was replaced about 3,000 miles ago and has appropriate tension (at least according to the mechanic who replaced it, and as best as I can tell. The compressor is definitely cycling on and off far more frequently than it ever has before a constant on/off, on/off really and it is also definitely making an extremely loud noise when cycling /running. That it did not ever make before. These things lead me to believe this is not normal cycling. I will check both sides. Any advice for best ways to tell if clutch needs adjustment or is going bad? I have looked at the basic DIY repair manual, but always looking for experienced, common sense help.
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Thursday, August 11th, 2016 AT 9:48 AM
Tiny
HMAC300
  • EXPERT
You have to use feeler gauges for clutch to see if its got correct air gap. But until gauges are thrown on and getting proper readings you are going in blind. The compressor could be going bad and if it did the system will have to be flushed as well as a new orfice and filter inline and drier replaced prior to evac and recharge.
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Thursday, August 11th, 2016 AT 9:56 AM

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