I just started the car.. and I looked under the hood, and as I'm looking at the pullies. I look at the AC compressor pully, and I notice periodically (roughly every 5 seconds.. but not exact.. it pretty random) Anyway.. the pully will be spinning from the belt driving it.. but then it will stop dead... but the belt keeps going obviously, slipping over the pully. And after a second or two.. the pully will "catch" and continue spinning.

Also.. when the pully stops.. it makes a fairly loud "click" noise. I've been hearing that noise for a while now.. but I alway thought it was metal expanding or something...

Could someone help me out on this? Is this normal?? Could this possible be causing what feels like a miss while driving? Because when I'm accelerating.. and it "clicks" the engine sort if "stumbles" or "misses" but I never really gave it a thought..

EDIT: sorry guys.. now that I look at it again.. it's not the entire pully that is stopping, and the belt isn't slipping around it. It is just the outer "face" of the pully. It does in fact look like it supposed to do that... but what is that?

Thanks

 

If you have the defrost on in the car the compressor will cycle on and off. Is the clutch actually locking up and the belt is slipping? If it is your compressor might be locking up.

 

Sounds normal for an a/c compressor. It cycles on/off whenever the system is in operation. It is not uncommon to feel a little thump or slight loss of power when it comes on. You will also hear it click on/off.

 

Ok.. thanks guys. I always thought it was a stumble of some sort.

 

it should not cycle if it is healthy. it shoud stay on or off depedning of if the switch is on or not. if the system is low or it is very cold out it will cycle.

 

Every car a/c that I have ever been around, the compressor cycles off and off as needed. Never have I seen one where the compressor stays on all the time. If the evaporator temp gets too cold, doesn't it tell the compressor to cycle off? Otherwise, you could get a freeze up condition.

 

only on cars that have a evap temp probe... but usualy the pressure is regulated more by fan contorl then compressor control. a normal healty system will have the cluctch engauges almost all the time and very the fan operation. usualy the low speed fans are on all the time and then when pressure gets high the high speed fans come on to lower the head presure and will shut off when t does. if the system gets too low while running the pressure switch will cut the compressor off (but even with the compressor always on and the fans on high it should never get that low) same for if it gets too high the swicth will stop the comprssor but again a heatly system wil never get that high. on the rare case that the pressur goes too low and the switch is bad the evap temp sensor will shut the compressor down. you usualy only see this sensor on an expantion system since the pressre can very more then an orifice system.

fan control is number 1 on controing pressure. unless it;s a very cool night with the ac on the compressor should run most all the time. ambiant temp has a lot to do with it