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Truck Trend Garage: 1997 GMC Sierra Squealing Belts

Alex Steele
Aug 31, 2010
Photographers: Steve Austin
Question: I have a 1997 GMC Sierra with the 5.7-liter engine. I replaced the idler pulley, tensioner pulley, and belt, but still have an intermittent squeal noise. Any ideas?
Photo 2/2   |   SQUEALING BELTS
Answer: It may be one of several serpentine drive or driven pulleys that are out of line. There's actually a special tool that uses a laser beam to determine proper alignment. But sometimes you can use a string (just like a bricklayer) lined up in common pulley grooves and accomplish the same thing. Or sometimes a good eye can pick it up by inspecting right where the belt begins and ends making contact with each pulley. In your case, there has been a notable problem with the power steering pump pulley being misaligned from the factory (or following replacement). Take a look at the front of the power steering pulley where the pump shaft goes through the center pulley hub. The shaft and the front of the pulley hub should be perfectly flush. If the shaft is sticking out past the hub, or recessed inward inside the hub, it's out of line. If so, it'll require a special power steering pulley puller/installer to align the pulley properly (perfectly flush). Typically there's enough room to do it without removing the pump. The pulley could very well be the problem, but check the alignment of everything just to be sure.

If you have a technical question regarding your pickup, SUV, or van, feel free to contact Alex, a master technician with the National Institute for Automotive Service Excellence. Send a letter to him in care of Truck Trend Garage, 831 S. Douglas Street, El Segundo, CA 90245, or e-mail us at trucktrend@sourceinterlink.com. Please include the VIN with your question. Due to the volume of questions received every month, we cannot guarantee that everyone's question will be personally answered or will appear in the magazine.
Can't wait for help with a problem you're having with your Truck or SUV? Ask the expert we trust here at Truck Trend Garage -- visit Alex Steele at www.RealWorldAutomotive.com.

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