Let me lay out all the facts first:



- Engine squeals about 50% of the time when driving around. It'll just suddenly start to make this horrible squealing/whirring noise while your driving.

- Squeal gets louder as the RPMs go up.

- If you hold the engine at any constant RPM, the squealing will stay at a constant volume.

- I can hear it just beginning to squeal at around 13-1400 RPM.

- Sometimes the squealing will just suddenly stop and the engine won't make a peep after that (no matter what RPM)

- It doesn't matter what gear its in (including neutral) and whether or not the clutch is in or out - the engine will squeal when you rev it.

- Sometimes (about 50% time) the engine runs just fine, no squealing, whirring, whining - nothing.

- I can't voluntarily make it start or stop squealing. It just happens on its own.

- Occasionally it will sound like there are 2 or 3 different squealing noises. (Has a different pitch.)



The squealing is very annoying, and I'm hoping its not something major. Any help or advice would be greatly appreciated.



Thanks --Matt

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Billerica, MA

Maybe the squealing is caused by a bad generator bearing or a bad water pump. When it starts saquealing try removing the generator belt then start the engine up again and see if it still squeals.

Could also be a generator belt, but I'm sure you've checked that.  Also, the damper ring on the front crankshaft pulley may have slipped back and is rubbing on the front mount (truck or T-Bird) or on the timing cover.

John in Selma, IN

John - "The Hoosier Hurricane"

Check the distributor. I have had a distributor with worn bushings do that.

John F

Ballwin, MO

Did you by chance have an anti-freeze leak recently?  If you get some of that on your belt it will squeal.  Can't be cleaned...buy another belt.

Gt

Gordie T           Long Point, Ontario

Hmm, I have checked the belt before, and it seemed to be okay. But I'll give it another look anyways. I have noticed in the past that sometimes drops of coolant end up on the inner fenders from the fan flinging it on there. So maybe coolant somehow gets on the belt too...



I highly doubt the squealing is coming from the distributor, water pump, or alternator because I've replaced all of those parts within the last year and a half.



Thanks for the replies --Matt

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Billerica, MA

Matt,If you have an alternator as you mention in last reply:a bad diode in the alternator will give exactly that squeeling noise.Hard to believe it will cause that noise  but it happened to me years ago.I am sure some of the other electrical experts on this site will say the same thing.There is a test but I am unsure whats involved.I just did a google search on "bad diode causes noise" and sure enough it says squeel increases as engine RPM increases.Have a look for yourself.Someone else here will know how to test it.

  

I wonder if I took the alternator over to the local AdvanceAuto to have it tested if we could find out if that's the problem.



Hey thanks for the tip, maybe someone else can chime in? --Matt

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Billerica, MA

Matt:If they have a proper tester they can tell pretty quick!Let us know what happens.