1998 S70 A/C belt pulley -- turn always?

mar601 · Post by **mar601** » 30 May 2017, 11:02

Just went out to put freon in my car and had the ac on full blast.

Should that pulley on the AC compressor be turning ALL the time because mine isn't turning at all -- and whos knows how long it's been like that.

No experience with AC on this car so excuse my ignorance. I imagine it should turn ? Can't be good on the serpentine belt.

Also -- if that's not a problem, I see I can check for a stuck clutch ? Is there also perhaps a realy I should check ? big thanks

mar601 · Post by **mar601** » 30 May 2017, 11:09

The pulley turns fine but now I'm starting to think that maybe the compressor loosened and just isn't engaging the belt? Adjustment for this? Like an alternator? Above or below the car?

Post by **theWIFES_S70** » 30 May 2017, 11:14

Not an a/c expert here. But from what I've seen and read, yes, it's supposed to turn. I'd take off the serpentine belt and inspect the belt for wear and double check that the compressor pulley is seized. Maybe it only looks like it isn't spinning? If the pulley is seized, you're putting your power steering pump and alternator and battery at risk... (And there's documentation of a ripped serpentine belt ruining a timing belt...) You can pop off the belt easy with a few quarters and a 1/2 breaker bar.

Edit:
The tension is set by the tensioner. There's no adjustment on our P80s. I'd pop off the belt and pop off off the tensioner assembly, it's only held on by two bolts (14mm?) Check to see if there's play. A new assembly is only around $50 bucks from our favorite retailers. Probably a hell of a lot less at a junkyard.

mar601 · Post by **mar601** » 30 May 2017, 11:49

The pulley isn't seized. As mentioned, it turns fine. So the belt tension feeding the compressor is solely controlled by the tensioner?

I'm already on FCP to order a new tensioner and belt. What about the 'tensioner pulley" and "idler pulley" ? I would like to replace these also if it isn't a pain or much added cost. I'm to the point where I have "my guy" do it -- he lets me buy my own parts.

Post by **theWIFES_S70** » 30 May 2017, 12:45

This piece is all you need to correctly set the tension on the serpentine belt. Replacing the pulley is only when the pulley stops spinning. The pulley doesn't set tension. The spring mechanism inside this thing does.

https://www.fcpeuro.com/products/volvo- ... m-1275380s

This is a pretty simple job, you should give it a try!

It's 15 mins.

The only other tensioners and idlers are for the timing belt. Those are separate from this. So all you'd need is this and the belt.

Post by **oragex** » 30 May 2017, 13:09

The pulley turns always with the belt, but the round plate over the pulley - the clutch plate, must turn/stop every few seconds or so.

If the clutch plate doesn't turn, the a/c clutch gap is too large preventing the clutch to engage (also make sure the small power wire to the compressor is well in place)

Post by **FLXC90** » 30 May 2017, 17:47

OP, yes the PULLEY should always turn with the belt. The clutch can disengage and remain stationary. If it does, it will appear at first glance that the pulley is not turning, because the center of the pulley, which is really the compressor hub will be stopped. They are concentric. If the Compressor does not engage, it could be the clutch gap, it could be electrical, or the simplest, you could be low on refrigerant pressure. The system has a low pressure cutoff that prevents the clutch from engaging to protect from loss of lubricating oil in event of a system leak.

I would take it to "your guy" and have him do a simple function/service check first. Should be $30-35 depending on your area. Many places do this cheap, so they can sell you the repair service needed.