namronorman

So, I have a belt squeal upon start up but only sometimes. Essentially, it happens after I've driven the car up to full operating temperature, shut it off, then turn it back on 2-3 hours later. Has anyone heard of such a thing? A lot has been replaced:

• Water pump
• Power steering pulley
• AC magnetic clutch
• Both idler rollers
• Tensioner pulley
• Alternator
• Belt multiple times

The amount of time the car must sit seems largely dependent on the ambient temperature and how fast the car cools down. During the winter, it seemed to happen after roughly an hour. During early spring, it seemed to happen after two hours. When it's warmer, it takes longer for it to happen. If I let the car sit overnight and come to a complete cool-off, it doesn't make the noise.

The folks I've been working with on the issue have been great about this entire ordeal and I mean no offense by asking, but sometimes more eyes and ears are helpful. If anyone I've worked with on this issue is reading this, thank you. I honestly do appreciate your help.

The car in question is a 2007 Carrera S with approximately 32k miles.

LexVan

All replacement parts are OE Porsche? Not aftermarket or OEM??

namronorman

All OE through a local Porsche dealer.

LexVan

You need to find someone who can fix and repair your car without throwing new parts at it. Who's paying for all this guess work?

There is an almost exact post like this one the 996 Forum. Might be a good read for you with further ideas.

namronorman

Looking at the video in the other thread real quick, it sounds pretty similar. Thankfully it's been a combination of the dealer and a warranty company paying for everything. My out of pocket expenses have been very low.

Ahsai

Has the tensioner itself been replaced? The tensioner is behind the tensioner pulley. Maybe it has lost it's tension, just a guess though.

How about the alignment of the pulleys and any abnormal wear on the pulleys and the belt?

Wait for the same condition you would expect the belt to squeal, then just remove the belt and hand spin all the pulleys and see if they feel any different.

Does it make a difference if you leave the a/c on or off before starting the car?

namronorman

Sorry, I should have clarified that the tensioner pulley and the assembly itself was replaced. It and the AC pulley were considered out of alignment and both replaced at the same time. I'm not sure if they've tested the pulleys when it should make the noise sans belt but I will ask next time I talk to them.

AC usage doesn't seem to affect noise.

In terms of when the noise happens, it does seem temperature dependent and it also seems it happens when the water temperature gauge is just below the first tick (110f-115f~). Perhaps the water pump that went in is bad or perhaps something is leaking onto the belt when things start to cool off but if it sits too long it evaporates? The thermostat was not replaced when the water pump was replaced unfortunately.

Ahsai

I doubt it's your water pump assuming you are not losing coolant. What I'm curious about is under such condition if you remove the belt and hand spin all the pulleys, whether any of them is harder to turn than normal therefore creating slip and squeal.

Macster

Quite a list. About all I can think of is the starter overrun clutch is dragging. Depending upon the severity this can produce squeal level noise.