Sierra 3500 2WD V8-6.6L DSL Turbo VIN 2 (2004)
Steps 3 - 5
The numbers below refer to the steps in the diagnostic table.
3. This test is to verify that the whine is being caused by the accessory drive components. Remove the drive belt and operate the engine for a few
seconds, this will verify if the whining noise is related to the accessory drive component. With the drive belt removed the cooling fan will not
operate and the engine may overheat. Also Diagnostic Trouble Codes (DTCs) may set when the engine is operated with the drive belt removed.
4. The inspection should include checking the drive belt tensioner and the drive belt idler pulley bearings. The drive belt may have to be installed and
the accessory drive components operated separately by varying their loads. Refer to the suspected accessory drive component for the proper
removal and replacement procedure.
