kjr914

Good ideas here for debugging the noise. Add a 4th, but low probability.....could also be a dying AC compressor bearing. But that's a longer shot than belts, so I was sticking to the most obvious first.

Ah, yes, thanks Alex! That's exactly it....couldn't find a pic with all of the writing showing and wasn't remembering the whole branding on the belt. I wasn't clear from OP if they were "Dayco" (OEM) or "Dayco Porsche" (OE) branding.

IXLR8

Which is why I like going for the process of elimination by taking one belt off at a time. A local 993er had a squeal and that is what I suggested doing. In his case, it ended up being the fan hub bearing.

MielsOnWheels

Thanks guys,all great suggestions and guidance. That's exactly why this forum is great. I'll let you know how it turns out!

DanL993

Quadcammer and VA993Dreamer: Can you guys please take that somewhere else? We have PM for these sorts of silly exchanges. They give me, and perhaps a number of others, a real pain!!

MielsOnWheels

Dan,

With respect, you're way off base calling me out. I did not ask Quad to post his smart *** comment in my post. If a comment like that is directed at me in the forum, I will respond in the forum and I will respond aggressively. If the comment was directed at me in PM, I will respond through PM. I suggest that if you have an issue, take it up with Quad. I and many others enjoy the civility and advice that RL offers and I for one won't tolerate people turning it into a platform for childish game-playing.

osugasman

VA993Dreamer: It looks like you will need to do the alternator pulley update while changing out the belts. The only downside is that the 2 sides are about $80 total so they add quite a bit to the cost. Also, suggest you get some new spare shims. This was recommended to me last summer. I did all the work myself (new to 993s and not a super great wrench) and it took around 2 hours. a/c compressor replacement on the 4 post was incredibly frustrating. I don't know if someone has a short cut to lining up the nut under the compressor while trying to put flexion on the compressor to get it lined up and then finally sliding the bolt through with your 3rd hand....

I get to do the whole thing over this weekend since I ignored a squeal in the brakes and destroyed the alternator belt. Used a krikit tool but with a break-in period and cold weather, I guess it got too loose.

Good luck.

Rutger Gert-Jan

I also had some squealing noise from the belts, I replaced my AC belt(original from de dealer)-> no more squealing now. If you are planning to do the up-date on the alternator pulley, why not change to the RS set-up? Saves you a belt

MielsOnWheels

Thanks for the info guys...pardon my ignorance but I had no idea there is an alternator pulley update out there, let alone the RS setup.

Could I get some education on the pulley update and why it should be done? (design flaw? more efficiency?) as well as the RS set up?

IXLR8

See attached Technical Service Bulletin...

kjr914

Its not clear to me from the picture that you actually need the pulley update....maybe someone else's eyes are better. In a nutshell (not counting the thin spacer shims):
Early alternator pulley: 4 total pieces (2-pulley halves, 2 tapered spacers)
Updated: 2 total peices (2-pulley halves with integrated tapered spacers)

This shows the old style pulley being replaced by an RS style fan hub.
https://rennlist.com/forums/964-foru...tl-photos.html

tangram

I had a problem with squealing and then throwing (twice) Continental belts. My mechanic had always used them up until about 2 years ago and then I had the problem. He said (who am I to doubt) that Continental had slightly changed the spec on the belts and that was what caused the problem. Switched to OEM and have had no real problem. A bit of squealing when I took the car out of storage this year and also recently when it got cold for the first time this Fall but at least the belts stayed on.

asofine

Bumping an old thread.

I'm now on my third instance of hearing some squealing over the last several years. The first time it actually threw the belt. The second time I isolated the problem to the tension sensor which I replaced. This time I've tried some WD40 on the sensor. I'm going on a road trip today so I'll report back.

pp000830

If the belts have been in the car for two years or more and considering that the effort to replace them is the same as adjusting their tension I would just replace them. Also I have always used aftermarket belt with no issues.
I also did the attached pulley update years ago. You can tell if you pulley has been previously updated as the original pulley halves are stamped steel and the updated parts are castings.
Andy

asofine

New belts, pulley update, yet there's still squealing back there. Bummer.

JB 911

From the technical bulletin Alex posted above

"The new version pulleys can also be installed on the 911 Carrera. However, the previous version belt
must be used."

Interesting note. The verbage for the turbo was "must" replace pulley. Carrera "can" replace pulley.

Asofine, you pickup that with the new pulley on a Carrera (non turbo), you still use the old belt?