C 2500 Truck 2WD V8-454 7.4L (1988)
Air Injection Hose/Tube: Technical Service Bulletins
A.I.R System - Increased Engine Noise
Number:
90-299-6E
Section:
6E
Date:
July 1990
Corp. Bulletin No.: 036605
Subject:
INCREASED ENGINE NOISE
Model and Year:
1988-90 C1, C3, K3, R2 TRUCKS WITH 7.4L (VIN CODE N) ENGINE
TO:
ALL CHEVROLET DEALERS
THIS BULLETIN CANCELS AND SUPERSEDES DEALER SERVICE BULLETIN NO. 89-66-6E, DATED JANUARY 1989. THE C1 TRUCK
HAS BEEN ADDED AS WELL AS THE 1990 MODEL YEAR. ALSO, CHANGES IN THE SERVICE PROCEDURE HAVE BEEN MADE.
DISCARD ALL COPIES OF 89-66-6E.
Condition:
Some 1988-90 C/K and R trucks with 7.4L engine and serpentine drive may receive customer comments of increased engine noise.
Cause:
Tube assembly between the Air Injection Reaction (A.I.R.) Management Valve and A.I.R. pump may be cracked or broken.
Correction:
A new design consisting of a bracket assembly, molded hose and adapter has been released. See the following Service Procedure:
