Hi All,

I just replaced a really noisy accessory belt tensioner... only to find a new noise that it was masking

I've narrowed the noise down to my A/C clutch. When idling and the A/C off there is a really loud high pitched whine coming from the passenger side engine bay. If I turn the A/C on the noise goes away and is replaced by the A/C noise (if that makes sense?) Anyway the noise is worse when the A/C is off.

I found that they do sell A/C clutch bearings... has anyone ever replaced one? Or maybe there is another reason for a noise like this?

BTW, the A/C works fine, ice cold air for as long as I want.

edit: I just found this video, my car sounds alot like this: . The uploader says it was definitely the clutch... but I'd still rather replace a $30 bearing than a $150 clutch.


Thanks!

 

I think you've correctly diagnosed a bad clutch bearing. I'm going to be doing this job soon on my Toyota Tundra. It's a bit easier on the Tundra but should not be too bad on your S40.

Biggest problem is access - you'll need to drop the compressor down a bit. Several YouTube videos on this - this one is helpful even though it's a Ford, but the compressor clutch type is similar.

 

Thanks migbro, great video. After watching it I could have the same issue as he had, with the noise coming from a worn clutch plate. In the video it looks like he did find it was just the plate but he went ahead and replaced the bearing anyway.

And if it is just the clutch plate on mine I might be able to get away with just removing a spacer to close the gap and not have to replace anything

 

Just pulled the belt off, and it looks like the bearing is toast. Spinning by hand and you can hear the bearing grinding a bit, and the pulley has a significant tick when tilting it back and forth. The clutch looks OK and isn't rubbing anywhere when released. Autozone has cheap Chinese knockoff bearings... I'm going to order an NSK off of Amazon.

Also looked at the gap between the clutch and the pulley. It's not too far off, but definitely out of spec:

Found these specs, I think for an 840...

Gap should be between 0.3mm/0.012in and 0.5mm/0.02in

I used my feeler gauge and measured 0.61mm/0.024in. I should be able to just remove one of the shims to get the gap back in spec.

 

Yikes, what a s**ty job! My NSK 35BD219DUM bearing came in today so I decided to replace the bearing today... on a gravel driveway... in the rain

I managed to do the whole thing with the ac compressor in place, didn't even have to drop it down. One of the ac hoses was kind of in the way, but not too bad.

The clutch is very difficult to remove. 10mm bolt off, then I bought a pack of M5x.8 bolts that you have to thread into the 3 holes in the clutch. The bolts bottom out against a lip on the compressor and push the clutch off. But that lip is narrow and made of aluminum so it got all chewed up.

Then the pulley. Snap ring off first. The bearing in the pulley is pressed onto the compressor... bastard is on tight too, and that ac hose blocks your every attempt to attach a puller to the pulley. Fortunately I have a smallish 2 jaw puller that I managed to get on it. 20 Ton Harbor Freight Shop Press ($149.99 on sale, worth its weight in gold!) and the bearing came right out. New one went right in.

So how to get the pulley back on... No tool to do that with, so I *gently* hammered it on part way until the 10mm bolt for the clutch could reach the spline with a few washers under it to press against the inner race of the bearing. The just screwed the bolt down the the pulley/bearing went on easy-er. But then you have to hammer again to get it on enough to reattach the snap ring. Done. (Having a longer bolt would have helped immensely, and would not have had to hammer the pulley on at first. Next time)

My clutch gap was ~0.6mm, so I decided to remove the spacer in the clutch. Only 1 spacer in there, and it was ~0.75mm thick So after pounding the clutch back on sans spacer, and tightening up the 10mm bolt, the clutch was making contact with the pulley. Errrgh! So back off goes the clutch a bit, then tighted down the bolt until the gap was ~0.3mm. Not ideal, but that clutch is extremely tight going on the spline, so I don't think it will move. I'll keep an eye on it and try to find a ~0.4mm spacer and put that in the clutch, or maybe just sand down the spacer I took out.

Thanks for all the help!

 

Wow. Good job. Better you than me.

I'm getting to the point where any job that requires lying on the ground next to or under my car is getting sent to the "pros" (lol). Unless the weather's perfect and I want to be outside. So many jobs are soooo much easier when the car is on a lift.

I think you'll find you'll have to redo this job with a spacer, btw.

 

My 40 yr old neck agrees with you, but my wallet says no. The rain wasn't a big deal, I had a 15x20 tarp draped over the hood and me, so I stayed dry. My wife thinks I'm an idiot for lying on the ground in a thunder storm... she could be right.

And yep, I'm looking for spacers now. I was thinking about it last night lying in bed, everytime that clutch engages its probably tapping itself closer and closer. I won't use the ac much until I get it fixed.

 

Exactly.

I'm 57 btw, so you have no excuse yet.