That #$%^ serpentine belt chirp again!


Full Access Member
Jan 30, 2020
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Another trick I've found that works well is floor dry. Throw a handful on the ribbed side of the belt with the engine running. It instantly silences the chirping.

Cant Write

Registered User
Sep 29, 2021
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Placerville CO
O’Rielly’s can order them in.

Also never assume a new/rebuilt part is any good. Story after story on this site of parts that are bad out of the box or failed shortly after.

One other thought, do your pulleys all line up? Perhaps The belt is sliding on your smooth pulley’s to move over for the next pulley that sticks further in or out. Thus chirping?
I agree with @Big Bart, you said they look straight. Have you used a laser, or a straight edge placed across the pully face butted up against the next pully or measured to the rear rib? Something that would give you a point of reference from pulley to pulley. Difference might be too small to measure or within tolerance.

I have never run into this problem except when the belt is due for replacement.

Thinking unorthodox, what about taking an old belt and cutting a couple ribs off, place it in the center, start the vehicle and see if it wants to walk one way or the other. Maybe the chirp is the shoulder of one pulley keeping the belt on?

V-belts for the win....haha. Honestly good luck!


Welding/metallurgical engineer/Metalsmith
Jul 13, 2015
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Granby CT
I will third(?) the pulley alignment. My 94 F Superduty had an idler pulley that was not aligned correctly and the belt would chirp constantly against the flange of the pulley. Eventually, it tore off a rib, then the belt chirped worse with the loss of friction. Checked the pulleys and the idler was in board towards the motor by about 3/16" or so. Found out there is a spacer that is supposed inside of it but its an optional piece and whoever installed the new pulley never put it in.

Ended up machining a spacer (I did it on a lathe out of 4140 steel but you could order a tube and cut it with a cutoff disc probably) and it is lined up perfectly now.