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?
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.
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