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300D Squealin' Like A Pig

During the last week or so I've been noticing a squealing noise occasionally coming from under the hood of my '91

300D 2.5. It sounds like a loose belt, and arises (1) when I'm braking, and (2) when I'm coasting downhill without the brakes being applied. There's no apparent relationship to steering inputs, so I've ruled out a loose belt on the power steering pump.

The noise seldom, if ever, arises when the engine is under load. And when it happens while the car is idling in drive, applying the brakes will usually cause it to stop. All of this sounds contradictory, which is why I'm puzzled.

Any ideas what the cause might be?

Geoff

Reply to
Geoff Miller
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"Geoff Miller" skrev i en meddelelse news:cnt869$ snipped-for-privacy@u1.netgate.net...

any ware on belt?

abs?

Reply to
news.tele2.dk

news.tele2.dk asks:

No discernible wear on the belt, and the belt certainly seems to be tight enough, with 1/4" - 1/2" play in it at the midpoint between pulleys. But you seem to be missing my point, which is: Why would the described conditions cause the belt to squeal in the first place?

Yes, my car has it; no, I don't feel it pulsing when I hear this noise. Remember, sometimes the noise becomes evident when I'm not even braking.

Geoff

Reply to
Geoff Miller

If your car has a belt tensioner I'd look at it rather critically, also its alignment with respect to the other pulleys.

Reply to
T.G. Lambach

Are you sure your brake pad is fine?

Reply to
Tiger

Yup -- they were all just replaced about a month ago.

I'm intrugued by T.G.'s suggestion that the belt tensioner might be the culprit. I'll take a gander at it this weekend.

Thanks, all.

Geoff

Reply to
Geoff Miller

I'd double check your brake pads... if you got abnormally wearing rotors, it will wear down fast.

I believe the tensioner is the culprit for squealing... but it doesn't have anything to do with braking.

Reply to
Tiger

The thing is, the rotors, like the pads, are brand new. Well, practically; they're about a month old.

More tellingly is that when I pull into my driveway, the noise often continues even after I've braked to a stop and I'm sitting there immobile with the transmission in Drive and the brakes applied. I've also heard the noise when the car has been idling with the transmission in Park.

Geoff

Reply to
Geoff Miller

Try to spray a little water to the belts, if the belts stop making that ignoring noise... you know what to do

Reply to
CSC

Or go to the local parts store and get a small can of belt dressing and spray the belts. Two dollars. This may be the cheepest fix you have. If this doesn't work, things get more expensive from here.

Larry In the back yard, under the oak .

Reply to
Central Florida

Sounds like belts to me, but a sticking caliper could be making for a little trouble - next time it happens try tapping the brakes a couple of times in succession just for the heck of it....

bad pulleys can cause squeal> Or go to the local parts store and get a small can of belt dressing and

Reply to
Terry Solomonson

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