Some 2001-2003 8.1-liter Chevy Silverados and Suburbans, GMC Sierras and Yukon XLs and 2002-2003 Chevy Avalanches may emit an annoying whining sound from the engine bay.
GM said the noise is most obvious at idle, varies in pitch as engine speed increases and is most likely due to the power steering pump pulley being too far inboard on the pump's shaft.
Start your diagnosis by taking a close look at the serpentine drive belt. If it's worn, especially around the outer edges, remove the belt. Now get a suitable puller and carefully reposition the pump pulley about .04-inch from the end of the pulley shaft. To complete the fix, install a new drive belt.
"Factory Fixes" is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via e-mail at tire[email protected].