kevin2012

My 1995 993 C2 has a noise AC pulley, it is the pulley bearing making the noise because when I remove the AC belt, the noise is gone.
I am going to replace the AC pulley bearing, may I ask the bearing parts no. or the spec ?
Thanks.

pp000830

Post the sound being made?

kevin2012

Pls see this link for the noise.
My alternator was changed last year with a Bosch rebuilt unit. All belts were changed last year.
Thanks
https://youtu.be/99NDs00yM24
Video was taken with AC on and engine fully warmed up.

pp000830

Doesn't sound like a bearing to me.
Sounds more like an air or refrigerant flow induced whistle.
A common complaint made of automotive AC systems.
I would not be so quick to take action.
Does it change or disappear at different engine speeds?
Andy

kevin2012

Thanks for your reply. I have a sport exhaust so I can hardly hear any of that noise when the car is moving. I normally hear it when the car is idling and more noisier when the engine is hot.
The noise is there no matter the AC is on or off but it is more notice when the AC is on.
I had tried to remove the AC belt and the noise is almost gone.

pp000830

If you can verify that the compressor is truly disengaging when you turn the AC off and you still hear the noise then it is not likely a flow related noise.
It seems to me this would also suggest the problem is not with the compressor but is related to the free spinning pulley. What happens if you put a few drops of oil on the pully so it runs down on to the shaft behind the pulley. Maybe just enough to eliminate the nosie issue, just a guess before going to the trouble of removing the pulley.

kevin2012

Thanks for the reply.
I am also thinking that it is the pulley issue too. Not sure where should I put the oil but I will try.
I am planning to replace the bearing for good and wondering what is the size or model of the bearing.
Thanks.

BobbyT

I'm not sure about putting oil in that area. The bearing in the AC clutch is a sealed bearing, so any oil you squirt in there isn't going to get into the bearing, but could do mischief dripping into somewhere it shouldn't be, such as belts.

Here is the link to a video of how to change the bearing:


I don't have the specs on this bearing. Most owners likely just change the entire clutch, less work and probably not much more expensive. For that matter, if the compressor itself is original to the car, you may want to just replace it before it decides to grenade the entire system. Not all that expensive unless you get the "genuine Porsche" one, still made by Denso...

kevin2012

Hi Bobby, thanks for your reply.
I would like to change the entire AC Clutch too but I had checked Pelican and the AC clutch is selling at $1000. Where can I get a cheaper AC clutch? Normally a replacement AC compressor will not come with clutch. Thanks.

BobbyT

I've found that most AC compressors are sold complete with the clutch. Case in point, the Pelican listing for the Denso compressor is complete with clutch.

I didn't find the Pelican listing for the $1,000 clutch--can you provide me the link?

kevin2012

Hi Bobby,
I used the part no. from Katalog to search, https://www.pelicanparts.com/cgi-bin/ksearch/PEL_search_2016.cgi?command=DWsearch&description=96412690101
but it is ok now as I can see a brand new AC compressor with Clutch they are selling now is only $332, I will just change the whole thing.
Thanks for helping out.

BobbyT

You are very welcome. This is a good time evacuate/recharge the system and to change the receiver-dryer, which has a desiccant component that becomes saturated over time and loses its effectiveness. Not an expensive part.

pp000830

Once you pull the old bearing out you can measure it or take it to a bearing distributor and for $20 or so replace it. Places such a Bearings Inc. https://www.bearingsinc.net/

pp000830

I always prefer the less-is-more approach to messing with my car. If the system is cooling well, I would avoid the urge to open up the system to change components as on a 20-year-old system you may be introducing problems where none exist presently.