One, and perhaps more, of my belt driven accessories seems to be making noise, albeit sporadically. It kinda sounds like the bearing in the alternator is going bad, but would it be correct to assume that the compressor pulley should not be hot enough to burn you? I haven’t run the AC in years, so the clutch shouldn’t be engaging. That pulley is getting really hot, so I may have a couple of issues, or the alternator is actually not making any noise. I believe the alternator is relatively new, but I don’t believe the compressor has ever been replaced or rebuilt.

With the exception of the idler pulley, all of the other pulleys are pretty warm to the touch, but the compressor pulley is literally hot enough to burn you. I saw a bit of smoke on the passenger side around the alternator after letting the car run for a while, but I wasn’t able to determine where it was coming from. It wasn’t heavy smoke and if I hadn’t been looking for something in that area I probably wouldn’t have even noticed it.

Feel free to move this if it should be in a different forum.

 

When the engine is running, is the outer (pulley) portion of the compressor clutch turning freely? It should be. If not, the pulley is stuck, belt is slipping and the friction is heating the pulley. When you turn on the A/C do you hear the clutch engage? Viewing Scan9495 will tell you if the clutch circuit is commanded on, and if the clutch circuit is active.

 

I would have to confirm, but I believe the pulley is turning freely. I was looking at things yesterday while the car was running, and I think I would have noticed if the pulley wasn't turning. I don't think I've turned the AC on since we pulled the car out of storage and I've been reluctant to turn it on for fear of damaging the compressor. I don't know if there is Freon etc. in the system. I don't know if that's a legitimate reason to worry, I guess I could try turning it on to see what happens.

When I mentioned the idler pulley earlier, I was actually referring to the tensioner pulley.

 

If the freon is low, causing low system pressure, the PCM will not allow the compressor to start.

 

Thank you for that info.

 

The pulley appears to be spinning freely. I turned the AC on, but the clutch never engaged. According to the scan, I believe the clutch circuit was commanded on, but it never activated.

 

There are codes (66 through 71) for the pressure sensor, clutch circuit, clutch relay, etc., and DTC 61 for A/C system performance. I've never dug into those because I deleted my A/C 20 years ago. There are readings in Scan9495 for A/C pressure, evaporator temperature, clutch status.

But as long as the clutch pulley is turning freely, it shouldn’t be the source of heat. You could play it safe electrically by unplugging the clutch harness connector - 2-wire dark green and black wires. Mechanically, I don’t know what components are inside the clutch assembly that could cause excessive friction/heat.

 

Take your belt off and spin everything by hand that should narrow it down if there is an issue. Could be a bad belt. Replace with a quality (gates, GM, dayco, continental, Bando) new while belt is off.

 

I’ll have to do some further investigation when I get a chance. The belt is a Gatorback. It’s been on the car for several years, but due to the fact the car has essentially been sitting in a shop I believe it’s pretty much new. I’ll check it out though. I think Continental may have bought Goodyear’s belt line. I just bought a Continental belt for my daily driver Grand Cherokee, but it’s not the Gatorback design.

 

I'm not sure how accurate the readings were, and there was some variance in the readings, but we used one of those infrared thermometers to measure temps on the pulleys. Most of them seemed to be 190ish, but the AC Compressor pulley read well over 300 the first time we took a reading. Some subsequent readings were under 300, but still much higher than the other belt driven pulleys.

 

A lot more action going on in the compressor could give you a higher temp reading vs the others?

 

I'm no compressor expert, but the clutch isn't engaged, so I'm assuming the pulley should just be spinning freely. It could have been like this for a while and I may have not noticed if not for the noise that it started making the last couple of times I drove it. I believe the noise is coming from the alternator, but we're not 100% certain of that.