Emissions - A.I.R. Adapter Noise
90chevy23GMC NUMBER: 89-6E-134
GROUP: 6E Engine Emissions
DATE: August, 1990
CORPORATE
NUMBER: 036605
SUBJECT: INCREASED ENGINE NOISE / NEW A.I.R. ADAPTER
MODELS: 1988-89 C3, K3 AND R2 TRUCKS W/7.4L (VIN CODE N)
CONDITION: Some 1988-89 C/K3, and R2 trucks with 7.4L engines 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:
SERVICE PROCEDURE:
(SEE ILLUSTRATION)
1. Remove old adapter.
2. On trucks that DO NOT have the support tab on the adapter tube, temporarily install new design hose, bracket and hose adapter to determine hole location for bracket.
3. Trucks that DO HAVE the support tab on the adapter tube will have one hole and weld nut already located on A/C Compressor / A.I.R. Pump Bracket.
4. On trucks with air conditioning, remove compressor from mounting bracket and lay to side. DO NOT DISCHARGE REFRIGERANT FROM SYSTEM.
5. On trucks without air conditioning, remove idler pulley bracket and save for reinstallation.
6. Scribe location of new bracket assembly on A/C compressor/A.I.R. pump. bracket.
7. Drill 5/16" hole/s in A/C bracket using new bracket assembly as template.
8. Install New Parts:
Parts are currently available through GMSPO.
9. Torque all bolts to 20-27 N.m. (14-20 lbs. lt.).
10. Reinstall A/C Compressor or Idler Pulley.
WARRANTY INFORMATION