Mysterious squeal coming from engine bay

[jdannucci]

My 2000 Boxster has been making a mysterious squeal at take off for quite some time (at least 1 1/2 yrs).

It only happens at take off, and only when I goose her a bit (quick take-off).

I feel it in the clutch pedal (almost like a slip) and is making me think that this could be a bad throwout bearing?

It has not gotten any worse or better in 20K miles.

I went to my Porsche mechanic:

He said that most likely the culprit was failing accessory belt pulleys that have worn out, so that when a significant amount of torque is dumped on them they squeal.

Has anybody ever had an issue like this??

Any info is greatly appreciated !

Jim

[logray]

+1 on the pulley, but if it is more of a whine it could also be the SAI pump. Various bearings including the wheels are known to make those types of noises.

It helps if you can have the car on jack stands or a lift and then go around to the various locations to see where the noise might be coming from.

It also helps if you can post a recording of the sound or video roughly from the location of it's source.

To isolate a pulley you can very briefly (just a few seconds) run the car without the serpentine belt. If the noise goes away you know it's a pulley or belt.

Edited May 23, 2011 by logray

[jdannucci]

It's a very short squeal that only last for maybe 2 seconds..

It never happens at idle, or while moving.. Just when you take off with a bit of mustard (fast takeoff).

[logray]

Can you reproduce/hear it sitting in neutral with the engine cover off and revving it? Or does the clutch have to be involved?

[jdannucci]

Hello,

The clutch has to be involved.

I'm guessing throwout bearing.

[logray]

Check your power steering fluid level too...

[jdannucci]

Well the noise is gone !!

I did a series of maintenance services this weekend including a new accessory belt.

I guess Dan Jacobs was right, his first guess at the noise was a worn belt or a bad pulley.

Cheers !!

Thanks for all the input.

[logray]

Nice work.

[ReyGabriel]

Your mechanic can be trusted because he did not point out to you a big job... he may be right...the belt accumulate dirt so much that over time...and its with oil, dust and all types of contaminant that are up in the air as you drive this hardens up the belts...the cheapest way is to clean the belt is with soap and water using a clean rug. You dont need to take it off the engine..You can reach it out as you scrub it back and forth...If this dont work try a pulley belt cleaner in spray can..

Its better to start with the easiest and the cheapest suspected trouble than be dreaded by all those slipping clutch, release bearing and all....believe me trust your mechanic.... the squeling sound you hear is usually when its raining and early in the morning when the belt has moist in it...When it squels the belt gets hot and dries up quick and goes to grips the pulley back again...

Edited May 23, 2011 by Loren