Engine squeal

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Dec 28, 2008 | 02:52 PM

bcjim

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Engine squeal

My 98 4.0 with 149K has developed a squeal. I thought it was a belt squeal, and it may be, but it doesnt seem like it from my cursory and brief (and unskilled) investigation. It is rpm dependent, it gets faster sounding when I hit the gas. Seems to have a bit of a cadence to it, its not a constant monotone squeal if you know what I mean. Disappears from time-to-time as well, but comes back. No codes. Seems to run ok, though I have not used it much since the noise showed up. No power loss or anything like that.

Any ideas?

Dec 28, 2008 | 04:18 PM

matt's2.9STX

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From: Southeast MI

Could be any of the accessories the serp belt runs around from your description, although I'd guess the idler off-hand from all that. Where does it seem loudest? Again, like so many other topics, you could probably use a mechanic's stethoscope, a small rubber hose around 3/8" ID or a 12" or so tube to use against your ear to focus on each part. With a tube, I'd go longer or better yet, use a brake or fuel line attached to a rubber hose.

Dec 28, 2008 | 04:22 PM

g_k50

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Have you changed your belt recently?
My understanding is that non Ford belts sometimes squeal due to an inexact V shape.

Dec 28, 2008 | 05:28 PM

pgw85706

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From: Lynchburg, VA

Idler pulley would be my first guess.

Dec 28, 2008 | 07:38 PM

drb1956

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From: Streamwood,IL

Quote:

Originally Posted by g_k50

Have you changed your belt recently?
My understanding is that non Ford belts sometimes squeal due to an inexact V shape.

I put a Goodyear Gatorback(serpentine), and its been nothin' but quiet, in all kinds of weather...I vote its a pulley on an accessory(power steering,air cond., etc..) and/or idler pulley, or the belt tensioner...You could TRY to squirt WD, or something like it while the truck is idling, just keep your hands out the fan, and keep your face out of the line of return fire when you spray. Try one thing at a time until it stops....