Suburban 1/2 Ton 2WD V8-5.3L VIN T (2004)
Hose/Line HVAC: Customer Interest
A/C - Hiss Noise From Instrument Panel
Bulletin No.: 06-01-38-002
Date: March 17, 2006
TECHNICAL
Subject:
A/C System Refrigerant Hiss Noise (Replace Liquid Line)
Models:
2003-2006 Cadillac Escalade Models
2003-2006 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2003-2006 GMC Sierra, Yukon Models
with 4.3L, 4.8L, 5.3L, 6.0L or 8.1L Engine (VINs X, V, T, Z, B, U, N, G - RPOs LU3, LR4, LM7, L59, L33, LQ4, LQ9, L18) and Air Conditioning
(RPOs CJ2, CJ3 and C69)
Condition
Some customers may comment on a hiss noise coming from the instrument panel. The noise has also been described as sounding like a gurgle or water
spattering. The noise occurs when the Air Conditioning (A/C) compressor engages and may continue for 5 to 10 seconds after the compressor disengages
or the A/C system is turned off. The noise is most noticeable when the vehicle is at idle or is being driven at low speeds. The noise is undetectable after
about one minute when the A/C system has been turned off or the vehicle has been turned off.
Cause
This condition may be caused by the expanding refrigerant as it passes through the orifice tube.
Correction
Technicians are to verify that the customer concern is only as described in the condition statement above. If the customer concern is a refrigerant hiss
noise, then technicians are to perform the normal diagnostic procedures for an A/C system concern. The ACR2000 should be used to check the A/C
system performance, charge level and discharge temperatures. This will eliminate the possibility that another condition is contributing to this customer
concern. If the A/C system is performing properly, and all other possible sources of this noise are eliminated, then technicians are to replace the A/C
liquid line. Use the proper part number as described in the parts information box below. Verify that the noise has been eliminated and that the A/C
system operates normally.
Parts Information
Important:
The trucks affected by this bulletin that have rear air conditioning were built with two different length condensers. The short condenser is 762 mm
(30.0 in) long. The long condenser is 914 mm (36.0 in) long. Be sure to measure the length of the condenser before ordering one of the tubes listed
below for vehicles with rear air conditioning.
