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Old 12-19-2000, 08:56 PM
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300D Squeal - Alternator ?

When I turn on the headlights with the rear defroster or the headlights with the front defroster I get a squealing sound from the engine. When I turn the defroster off the sound stops. I also get a 1 second squeal when I start the car. Squeal is present while not moving with foot on pedal. Can I make an adjustment or do I need to replace a part? How long have I got until it fails? Which part? (Belt, Alternator, other?).

Fareed M.
1978 300D

[Edited by Trius91 on 12-19-2000 at 10:02 PM]
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Old 12-20-2000, 12:28 AM
Larry Delor's Avatar
What, Me Worry?
Join Date: Jun 1999
Location: Sarasota, Fl.
Posts: 3,026
If your '78 has two alternator belts like my '83 then either your belts are very worn out, or most likely loose, and they need to be tightened. Push on the belts with your fingers, and see how much deflection you are getting. (Engine off, of course) I bet it is more than 3/4 of an inch.
"...rationality of thought imposes a limit on a person's concept of his relation to the cosmos." -Nash

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Old 12-20-2000, 08:46 AM
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Larry is right on. If the belts are indeed properly tensioned, remove them and spin the alternator by had to see if the bearings are smooth. However, I'll give Larry's suggestion about a 98% chance of success.

Good luck and Merry Christmas,
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Old 12-27-2000, 05:24 PM
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Tightening the belts fixed it. Thanks.

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