Canyon 4WD L5-3.5L VIN 6 (2004)
Balance Shaft Chain Tensioner: Customer Interest
Engine - Whine or Rattle On Light Acceleration
Bulletin No.: 04-06-01-016B
Date: March 30, 2006
TECHNICAL
Subject:
Underhood Whine or Rattle Type Noise (Replace Tensioner)
Models:
2004 Chevrolet Colorado
2004 GMC Canyon
with 3.5L L5 Engine (VIN 6 - RPO L52)
Built Prior to VIN Breakpoints 48123220 (Chevrolet) and 48123225 (GMC)
Supercede:
This bulletin is being revised to update the warranty information. Please discard Corporate Bulletin Number 04-06-01-016A (Section 06 -
Engine/Propulsion System).
Condition
Some customers may comment on a whine type noise and/or a possible rattle noise on light acceleration coming from the engine. This noise may seem
more pronounced at start up after an overnight soak.
Cause
The source of the noise may be the balance shaft chain and the tensioner interaction. There are 2 balance shafts in this engine that are driven by the
crankshaft to keep the engine running smoothly. This noise does vary from vehicle to vehicle and does not cause any durability concerns however, some
customers may find it objectionable.
Correction
A new tensioner has been designed to eliminate this noise. The kit consists of an oil fed tensioner, longer tensioner bolts, balance shaft drive chain and
right side balance shaft assembly. Please note that it is necessary to install the updated balance shaft assembly because it contains an oil feed passage for
the oil fed tensioner.
This new tensioner was introduced into production in the mid December time frame. If you have a vehicle built prior to VIN breakpoints 48123220
(Chevrolet) and 48123225 (GMC), install a new tensioner, P/N 89017543.
Follow the removal and installation instructions in SI for the Balance Shaft Chain Tensioner Replacement in the Engine Mechanical sub-section. You
will also need to order and install a new rear oil seal, P/N 12568124.
Parts Information
Warranty Information
