My fan belt was making a screeching noise, so I replaced the belt. No noise for awhile, then it started screeughching again. If I spray WD-40 on the belt while the engine is running it stops. After running for a minute or so the screeching starts again. What could be making the belt screech? I appreciate your time.


Hugh W. Smith, Sr.


1984 190d 2.2L 124,545

Belts only squeal for two reasons that I know of:

1. Too loose.
2. Stuck or dragging accessory creating too much load.

Why exactly did you spray WD-40 on your belts?

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

IIRC an '84 190D has a serpentine belt. It's really unusual for a serpentine belt to screech. Remove the belt and check all the pulleys, particularly the tensioner pulley. Check that the tensioner arm pivots smoothly without clicking and doesn't wobble. Check also that all the pulleys are on the same plane. A worn tensioner can cause the tensioner pulley axis to shift.

Sixto
87 300D

Please ring up our Corolla and let it know. It's very confused.

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1982 300SD -- 211k, Texas car, tranny issues ____ 1979 240D 4-speed 234k -- turbo and tuned IP, third world taxi hot rod

2 Samuel 12:13: "David said to Nathan, “I have sinned against the Lord.” And Nathan said to David, “The Lord also has put away your sin; you shall not die."

I was standing in front of my car wondering what could be causing the screech, and noticed a can of WD-40, and thought, why not.

You can fix it and save me the step of telling it to ask you to fix it

Sixto
87 300D

Probably not too good for the belt. It is common to use plain water. But I have used other stuff in a spray bottle that happened to be handy myself - but at least water based.

If it is a serpentine belt, does it have an automatic tensioner? If so, it might not be working properly and not getting enough tension on belt. Check the manuals or a specific site for your car. Perhaps there is an adjustment. Inspect the belt both sides - may also tell you something. If no luck, remove belt and check all components turn freely. Also make sure all pulleys line up properly.

I know nothing about that car, but have serpentine belt on our E320 that broke once a high speed no access elevated expressway. Not fun! Get her properly fixed! Shop did mine for about $200 plus towing paid for by insurance co.

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

the 190 2.2 should be the same belt system as the 87's 603's... screeching could be, bad spring tensioner, bad shock, a bad bearing on one of the components being turned by the belt... (think, alternator) or even an excess load, on one of the components being turned... a bad voltage regulator could cause the alt to have max amp load, which would fry your battery... the power steering pump could have fluid that turned to sludge... the water pump could be bad, the aux fan clutch could be locked on, and overloading the belt...
like was said, I'd pull the belt off, and spin by hand all the components with the key on. for the fan clutch, grab it, and see if the fan will turn the motor over... or slip on the belt... the fan should turn freely...

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My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Gates has a youtube video where they show how to diagnose problems with multi-V (serpentine) belts. One trick is to spray water on the belt grooves to see if the squeal goes away, which proves (I forgot, belt is old?). Multi-V belts are very unforgiving of any misaligned pulley, so that is a common problem. Regular V-belts can tolerate up to 1/8" misalignment. You can get some sticky stuff at auto parts to give a better grip.