Alternator wail W124 M102 - PeachParts Mercedes-Benz Forum

vegadonovan · #1 10-10-2007, 07:48 PM

Hi all,

I have got this wailing alternator after I sprayed some engine degreaser on it to make it look better. Yes I know I shouldn't have done that now.

It seems that the lubricant on the bearing could have been dissolved. Can I spray some WD40 into the area where it holds the belt to alleviate the problem or its a no no?

Thanks !!!

Ethan · #2 10-11-2007, 06:31 PM

I think WD40 is more of a cleaner then a lubricant.

rorypff · #3 10-12-2007, 01:35 AM

Might get away with regreasing the bearings but either way you will have to remove the alternator and strip it. I would replace the bearings for peace of mind.

vegadonovan · #4 10-12-2007, 04:19 AM

Dear all,

Just an update and close this;

the wail doesn't come from the alternator. It came from the belt.

Spraying water on it remove the noise totally and the belt was changed 1 month back. Continental or some like that.

The mec says to change it to some other brand when he was the one who fitted it in... And even suggested changing out ALL the pulleys... $$$$$$$

He must be crazy. So I left.

Bought a belt dressing and sprayed it. Noise became worst. Sprayed with water and noise was gone.

Will live with it until I find a solution other than changing it out.

Thanks

Ethan · #5 10-12-2007, 08:45 AM

I've read belt dressing is bad stuff, and should never be used.

You may want to try with engine off, clean the inner surface of the belt and the exposed surface of the pulley with a danp cloth.

Why not just change out the offending belt?

rorypff · #6 10-12-2007, 09:18 AM

A serpentine belt can not make a noise unless there is major misalignment of the pulleys - you definitely have a bearing problem on one of the pulleys. The water just acts as a temporary lubricant, that's why the noise disappears for awhile.

vegadonovan · #7 10-12-2007, 10:46 AM

I will change out the belt soon. Just not at the same dealer.

He was saying : " Do you want to change out the belt? Oh yes you can and the noise will be gone today. But then again, the noise will come back after a week or two. By the way its an old car. 9 out of the has them....."

I didn't have this bloody problem till my ass itch and I went to him to fixed the tensioner; that opened the infamous box.

And he mentioned that the groves on the pulley might be too sharp which will inadvertently cut into the belt and cause such a noise. Again, changing the pulley was what he was trying to upsell.

sigh..

brewtoo · #8 10-12-2007, 12:24 PM

Quote:

Originally Posted by rorypff

A serpentine belt can not make a noise unless there is major misalignment of the pulleys - you definitely have a bearing problem on one of the pulleys. The water just acts as a temporary lubricant, that's why the noise disappears for awhile.

The belt is probably simply slipping. It still slips when you put water on it, you just can't hear it.

I don't think there's anything wrong with Continental belts. I think MB used those when they built this car.

Is the belt properly tensioned?

vegadonovan · #9 10-12-2007, 09:28 PM

Hi Brew,

The reason that started all this was I found the engine bay noisy.

So I went to this dealer and ask them to remove some noise;

1) They found the Tensioner damper bushing worn out creating a rattle
2) Tensioner was fine but belt was way too lose. About 3 inches of slack.
3) Belt has mirco cracks

So the belt was replaced. Tensioner damper was repaced. And the belt tightened. Tensioner itself was not replaced due to high prices altogether.

Well the tensioner broke 3 weeks after. Had to change it out there again.

Now the wail.

By the way , belt has virtually no slack now. I wonder if there is such a thing as overtightened belt.