Chirping and squealing serpentine belt

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austinado16

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Todd
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1990 w/307k miles on the clock
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GMC V1500 Suburban SLE
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5.7L TBI/4L60/3.42's
Thought the water pump bearings were failing today during a drive. Removed the alternator and had it spun in a machine to see if it's bearings were the cause.....nope. Replaced the serp belt tensioner pulley at $22 because it was right in line with where the noise was coming from.....no change. Replaced the serp belt idler next......no change. Then the decided to spray the ribbed side of the serp belt with some TriFlow and the noise immediately went away.

Friggin' NAPA brand belts!

Installed a Dayco, now it's nice and quiet again.
 

89Suburban

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Gatorbelts are nice and quiet too.
 

skysurfer

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+1 on the Gatorbacks.
 

austinado16

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1990 w/307k miles on the clock
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GMC V1500 Suburban SLE
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5.7L TBI/4L60/3.42's
Ya. Used to feel like NAPA sold quality stuff. I'm not seeing proof of that any more. Just put a set of their V-belts on my VW pickup, and the alternator belt could not be kept from squealing, no matter how tight. Purchased a set of Dayco belts, and have had no further issue.
 

austinado16

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Joined
May 25, 2012
Posts
611
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221
Location
Central Coast, CA
First Name
Todd
Truck Year
1990 w/307k miles on the clock
Truck Model
GMC V1500 Suburban SLE
Engine Size
5.7L TBI/4L60/3.42's
SOLVED FINALLY...

So the problem has continued, even after replacing the Serp belt. It would go away after 30min of driving, and not typically return until the next cold start. The noise would temporarily disappear, if the belt was given a shot of spray lubricant, but then come back even worse a few minutes later. The noise was definitely coming from the water pump...but of course it would go away w/ a shot of spray lube, so I knew it was just the belt, or pulley, or how the belt was riding on the pulley.

Started thinking: The last thing I did to this area of the engine was to replace the P/S pump, which of course has a pulley that has to be pressed on to a certain depth......d'oh. I laid a straight edge across the P/S pulley and it was about 3/16" out of alignment with the water pump pulley, causing the belt to contact the forward-most raised edge, hence the squeal. So I used the P/S pump pulley installer tool to shove the pulley in further, until the pulley was flush with the center hub of the P/S pump shaft, and the squeal is gone. The belt now rides centered on the water pump pulley.
 

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