Engine Squeak and Alternator Pulley Slips Counterclockwise

[gbennett]

The car is a 2003 C4S manual transmission. It just turned 70k miles this week.

I was (still am) trying to diagnose an ever-increasing squeaking coming from the engine bay. My first effort was to remove the poly belt to check the pulleys for excessive play. When I got to the alternator pulley, I noticed that I could freely turn the pulley counterclockwise while holding the alternator still by holding on to one of the fins, If I tried to turn the pulley clockwise while holding the alternator from turning, it would not slip.

I see that the engine turns this pulley clockwise naturally, but is there still a way this could be causing the noise?

As for the squeaking, it comes on as soon as I start driving (it does't squeak at idle) and comes on intermittently. It initially was more closely tied to turning, but now squeaks regardless of turning, accelerating, etc. That is, I can be cruising with minimal load on the engine and it still squeaks on and off. Also, the squeak does not change get higher or lower with engine rpm. I noticed it this morning for the first time, and after driving maybe 20 miles, it has gotten increasingly more frequent.

Any ideas?

I appreciate your help. This board has come to my rescue numerous times!

Greg

[Loren]

:welcome:

Alternators on non-Tipronic are free wheel pulleys that do not lock - so that is normal.

Best thing to do is remove the belt and rotate each pulley - spin them if possible.

If there is any any wobble replace them.

[RFM]

Check also the power steering fluid level, with a too low fluid level, the steering pump will squeak.

[gbennett]

Thanks for the quick replies gents! I just sources some Pentosin, so I'll try to top off the power steering fluid and see if that helps. I'll report back!

[djm999]

:welcome: Alternators on non-Tipronic are free wheel pulleys that do not lock - so that is normal. Best thing to do is remove the belt and rotate each pulley - spin them if possible. If there is any any wobble replace them.

Are the pulleys on the alternator, a/c compressor and power steering pump replaceable?  I am tracking down an occasional whine and all of these pulleys seem to be candidates.  I've replaced the idler pulleys and tensioner pulley.  I am getting a little squeak/squeal from the power steering pulley but I don't know if it is the pump or just the pulley that is making the noise.

[Loren]

Yes, all are replaceable (Alternator, AC, and power steering.

Use an engine stethoscope to find the location of the noise.

[djm999]

Thanks Loren,

 

The noise appears to be coming from the power steering pump pulley area.  I was told by a parts supplier that replacing the pulley would not affect the noise because the noise is always in the pump, therefore, they don't sell the pulley separately.  Should I consider the pulley replacement or is it time for the pump to go before it goes on it's own?

[djm999]

One more related question... the inner hub on the power steering pump pulley is not turning when engine is running.  should it be turning when the outer pulley is turning?

[Loren]

I believe he is correct - the pulley is just a pulley and the bearing is in the pump housing.

Looks like a new pump is in order.

[RFM]

What you mean with "inner hub" are you sure it's about the power steering pump pulley? By a broken shaft/pulley combination you have no more power steering and/or the combination simply falls off. Your specified pully combination refers more to the AC compressor or alternator with free wheel pulley, the explanation sounds a little confusing to me.

[Ahsai]

What you mean with "inner hub" are you sure it's about the power steering pump pulley? By a broken shaft/pulley combination you have no more power steering and/or the combination simply falls off. Your specified pully combination refers more to the AC compressor or alternator with free wheel pulley, the explanation sounds a little confusing to me.

Yeah, I was wondering the same.

[Ahsai]

We're talking about the silver pulley and not the black one, right?

http://www.ramspeedautomotive.com.au/blog/wp-content/uploads/2012/03/Porsche-996-4S-Carrera-Grey-Supercharger-Upgrade-Ramspeed-3.jpg

[djm999]

We're talking about the silver pulley and not the black one, right?

http://www.ramspeedautomotive.com.au/blog/wp-content/uploads/2012/03/Porsche-996-4S-Carrera-Grey-Supercharger-Upgrade-Ramspeed-3.jpg

Sorry for the confusion, I am talking about the black one in the photo link above.  The pulley on the perimeter is spinning but not the black flat center section.  I can't remember if it is supposed to spin.  Thanks,

[Ahsai]

 

We're talking about the silver pulley and not the black one, right?

http://www.ramspeedautomotive.com.au/blog/wp-content/uploads/2012/03/Porsche-996-4S-Carrera-Grey-Supercharger-Upgrade-Ramspeed-3.jpg

Sorry for the confusion, I am talking about the black one in the photo link above.  The pulley on the perimeter is spinning but not the black flat center section.  I can't remember if it is supposed to spin.  Thanks,

 

That's the a/c pulley. It's normal the pulley center is not rotating when the a/c is OFF. When a/c is ON, the center should rotate as one piece with the pulley all the time.

[djm999]

Thanks for the clarification.  You guys are the best