Savana 4500 V8-6.6L DSL Turbo (2009)
Drive Belt: All Technical Service Bulletins
Diesel Engine - Drive Belt Chirp/Squeal at Cold Idle
TECHNICAL
Bulletin No.: 05-06-01-018B
Date: February 09, 2011
Subject: Accessory Drive Belt Chirp, Squeal or Squeak Type Noise at Cold Idle (Replace A/C Compressor/Power Steering Pump Mounting Bracket or
Enlarge Bracket Bolt Holes)
Models:
2004-2010 Chevrolet Silverado
2006-2010 Chevrolet Express
2004-2010 GMC Sierra
2006-2010 GMC Savana
Equipped with 6.6L Duramax(R) Diesel Engine (VINs D, 2 - RPOs LBZ, LLY, LMM)
Supercede:
This bulletin is being revised to add model years and RPOs. Please discard Corporate Bulletin Number 05-06-01-018A (Section 06 - Engine/Propulsion
System).
Condition
Important
It should be noted that a chirp type noise on engine shutdown is normal for a diesel engine due to higher engine compression and the rapid
stopping of the crankshaft. No repairs should be attempted for this condition.
Some customers may comment on an accessory drive belt chirp, squeal, or squeak type noise at idle, especially on a cold start. The noise may be reduced
or go away after the engine warms up.
Cause
Some 2004/2005 Silverado or Sierra trucks, with a 6.6L LLY engine produced before June, 2004, may have an A/C compressor/power steering pump
mounting bracket and power steering rear mounting bracket that are machined slightly out of specification, causing a misaligned power steering pump.
If the power steering pump is misaligned, it will force the accessory drive belt to run farther inboard on the fan pulley. When the belt leaves the fan
pulley, the belt will not align properly to the crankshaft pulley grooves and create a chirp or squeak type noise at the point of interference.
Vehicles built after June 2004 will already have the new A/C compressor/power steering pump mounting bracket installed, but still may exhibit belt
noise caused by the power steering pump rear mounting bracket.
Correction
Vehicles built prior to June 2004, replace the A/C compressor/power steering pump mounting bracket.
Vehicles built after June 2004, enlarge the rear power steering pump bracket bolt holes.
1. Follow the published service information (SI) diagnostics for drive belt chirping. The diagnostic chart for the drive belt chirping will ask to inspect
for a misaligned accessory drive pulley.
Important
Remove the top section of the radiator shroud and TCM/cover to gain access to check alignment and measure the power steering pulley
on the power steering pump shaft.
2. Verify that the power steering pulley is properly pressed onto the power steering pump shaft. Refer to SI for the power steering pulley
replacement. If the pulley needs to be realigned on the power steering pump shaft, follow the published SI procedures for the power steering pulley
replacement.
