K 2500 Truck 4WD V8-379 6.2L DSL VIN C FI (1989)
Hose/Line HVAC: All Technical Service Bulletins
A/C - Moan, Vibration, Noise When Compressor Engaged
GMC NUMBER:
90-1B-111
GROUP:
1B-AIR CONDITIONING
DATE:
NOVEMBER, 1990
CORPORATE
NUMBER:
061201
SUBJECT:
AIR CONDITIONING MOAN / VIBRATION / NOISE
MODELS:
1988-90 C/K LIGHT DUTY TRUCKS WITH AIR CONDITIONING (RPO C60)
Some 1988, 1989 or 1990 C/K model trucks may develop a condition described as a moan, vibration, or noise when the A/C compressor is engaged. To
address this condition, Harrison Radiator has released a suction-discharge hose assembly for service. This new hose assembly will be made of a different
material, (nitrile), than the production assembly and dampens more vibration.
Important
The revised hose assembly alone will not solve all customer comments. It is essential that the revised service hose be used only after the following noise
abatement procedures have been employed.
^
Check A/C system for grounding (hoses/pipes hitting hoses/pipes, body or engine).
^
Check mounting bolts for being loose, missing, or a blind hole.
^
Check drive belt for debris in the grooves or for wear.
^
Check that a brace kit has been installed from bulletin 88-T-56 (filed in group 1B) (Corporate Number 831203).
^
Check that the latest R4 compressor is being used. All 1990 Model C/K trucks were built with the latest style A/C compressor. When
repairing 1988 and 1989 model C/K trucks, reference Truck Service Bulletin 89-1B-118 (Corporate Number 961205). To determine whether
the new nitrile hose assembly will lessen the A/C noise-moan-vibration, have a person in the cab listen to the noise at the engine speed where
the noise is most prevalent. Have another person in front of the truck grab the suction hose with both hands. This will approximate the noise
reduction which will result from replacement of the hose.
SERVICE PARTS INFORMATION
Nitrile Hose Assembly
Parts are expected to be available on November 19, 1990. Until then, normal part orders will not be accepted by GMSPO. Only verifiable emergency
VIP orders will be accepted. GMSPO will make every effort to obtain parts. All parts will be placed on 400 control to waive VIP surcharges. However,
the parts will be shipped premium transportation at dealer's expense. All other order types will be canceled as incorrectly ordered while 400 control is in
place.
WARRANTY INFORMATION
For vehicles repaired under warranty use:
