Colorado 2WD L4-2.8L VIN 8 (2004)
Evaporator Core: All Technical Service Bulletins
A/C - Whistle/Hiss/Hum or Ring Noise With A/C ON
Bulletin No.: 04-01-38-012D
Date: June 27, 2006
TECHNICAL
Subject:
Whistle/Hiss/Hum/Ring Noise Heard When A/C is On (Replace Evaporator Core and Liquid Line)
Models:
2004-2005 Chevrolet Colorado
2004-2005 GMC Canyon
with Air Conditioning (RPO C60)
Supercede:
This bulletin is being revised to update the labor time information. Please discard Corporate Bulletin Number 04-01-38-012C (Section 01 - HVAC).
Condition
Some customers may comment on a whistle/hiss/hum/ring noise that is heard inside the vehicle. The noise emanates from the compartment area of the
instrument panel (IP) when the air conditioning (A/C) is on. Technicians may hear the noise every 15-60 seconds and the noise lasts for 2-5 seconds. The
noise occurs when the A/C compressor cycles on. This condition does not indicate a defect in the A/C system, but the noise may be objectionable to the
customer.
Cause
This condition may be caused by refrigerant flow through the evaporator core when the A/C compressor cycles on during normal operation.
Correction
Technicians are to replace the evaporator core and liquid line with updated design parts. Replace the evaporator core with P/N 89018834. Refer to the
Evaporator Core Replacement procedure in the HVAC section of SI. Replace the evaporator tube (liquid line) with P/N 89024923. Refer to the
Evaporator Tube Replacement procedure in the HVAC section of SI.
Parts Information
Warranty Information
