CAMPAIGN: COOLANT LEAK FROM AUXILIARY REAR HOSE ASSY.
SUBJECT: COOLANT LEAK FROM THE AUXILIARY REAR HEATER HOSE ASSEMBLY
MODELS: 1992 CHEVEROLET AND GMC C/K SUBURBANS EQUIPPED WITH 7.4L ENGINES (L19) AND AUXILIARY REAR HEATER (C36)
General Motors of Canada Limited has determined that some 1992 Chevrolet and GMC C/K Suburbans equipped with 7.4L engines (L19) and auxiliary rear heater (C36) may develop an engine coolant leak from the auxiliary rear heater outlet hose. The leak is caused by a heat deterioration of the hose material as a result of its close proximity to the right-hand exhaust manifold. The leak could eventually result in a total loss of engine coolant.
To correct this condition a new rear heater inlet/outlet hose assembly with protective heat insulation will be installed.
VEHICLES INVOLVED:
Involved are certain 1992 Chevrolet and GMC C/K Suburbans with 7.4L engines (L19) and auxiliary rear heater (C36) built within the following VIN:
MODEL PLANT YEAR MODEL PLANT CODE FROM THROUGH ----- ----- ----- ----- ---- -------- 1992 GMC C/K 20906 Janesville J SOP NJ722495 1992 CHEVROLET C/K 20906 Janesville J SOP NJ345036
All affected vehicles have been identified by the VIN listing provided to involved dealers with this bulletin. Any dealer not receiving a listing was not shipped any of the affected vehicles.
DEALER CAMPAIGN RESPONSIBILITY:
Dealers are to perform this campaign on all involved vehicles at no charge to owners, regardless of kilometres traveled, age of vehicle, or ownership, from this time forward.
Whenever a vehicle subject to this campaign is taken into your new or used vehicle inventory, or it is in your dealership for service, you are to ensure the campaign correction has been made before selling or releasing the vehicle.
Owners of vehicles recently sold from your new vehicle inventory are to be contacted by the dealer, and arrangements made to make the required modification according to instructions contained in this bulletin.
CAMPAIGN PROCEDURE:
Refer to Section 4 of the Service Policies and Procedures Manual for the detailed procedure on handling Product Campaigns. Dealers are requested to complete the campaign on all transfers as soon as possible.
OWNER NOTIFICATION:
All owners of record at the time of campaign release are shown on the attached computer listing and have been notified by first class mail from General Motors. The listings provided are for campaign activity only and should not be used for any other purpose.
PARTS INFORMATION:
Parts required to complete this campaign should be ordered through regular channels, as follows:
Part Number Description Quantity/Vehicle ----------- ----------- ---------------- 15961911 C-Truck: Auxiliary Heater Hose Assembly 1 15961912 K-Truck: Auxiliary Heater Hose Assembly 1
PARTS AND LABOUR CLAIM INFORMATION:
Credit for the campaign work performed will be paid upon receipt of a properly completed campaign claim card or DCS transmission in accordance with the following:
Repair Code Description Time Allowance ----------- ----------- -------------- 2A Replace Auxiliary Heater Inlet and Return .8 Hose Assembly
Time allowance includes 0.1 hour for dealer administrative detail associated with this campaign.
Parts credit will be based on dealer net plus 30% to cover parts handling.
SERVICE PROCEDURE:
1. Replace the auxiliary heater inlet and return hose assembly with the new design auxiliary heater inlet and retum hose assembly following the procedure found in the 1992 Chevrolet C/K Truck Service Manual ST375-92 and the 1992 GMC C/K Truck Service Manual X-9231.
2. Loosen the two fasteners which secure the air intake pre-cleaner bracket to the wheel well. They are located inside the passenger side front wheel well.
3. Loosen the single fastener which secures the auxiliary heater pipe assembly to the air intake pre-cleaner bracket.
4. By pulling/pushing/rotating the auxiliary heater pipe assembly, use the relative movement between the loosened components to maximize the distance between the auxiliary rear heater hose assembly and the exhaust manifold.
5. Once the maximum distance is obtained, hold the position and retorque the air intake pre-cleaner bracket fasteners to 18 N.m (159 in. lbs.) and the auxiliary heater pipe assembly fastener to 18 N.m (159 in. lbs.).
6. Using a shop scale, measure the distance between the auxiliary rear heater hose assembly and the passenger side exhaust manifold at their closest point. The required minimum clearance is 12.25m/1/2 inch. If the required minimum is not obtained repeat steps 2 through 6. If minimum clearance is still not obtained the air inlet pre-cleaner bracket and auxiliary heater pipe assembly bracket can be removed and the holes in the wheel well and auxiliary heater pipe assembly bracket can be elongated or enlarged to allow more clearance.
7. Install a "Campaign Identification Label."
INSTALLATION OF CAMPAIGN IDENTIFICATION LABEL
Clean surface of radiator upper mounting panel and apply a Campaign Identification Label. Make sure the correct campaign number is inserted on the label. This will indicate that the campaign has been completed.
COPY OF CUSTOMER LETTER
Dear General Motors Customer:
General Motors of Canada Limited has determined that some 1992 Chevrolet and GMC C/K Suburbans equipped with 7.4L engines and auxiliary rear heater may develop an engine coolant leak from the auxiliary rear heater outlet hose. The leak is caused by a heat deterioration of the hose material as a result of its close proximity to the right-hand exhaust manifold. The leak could eventually result in a total loss of engine coolant.
To prevent this condition from occurring, your dealer will install a new rear heater inlet/outlet hose assembly with protective heat insulation.
This service will be provided for you at no charge.
Please contact your GM dealer as soon as possible to arrange a service date.
If parts are required, ask your dealer for details regarding their availability. If parts are not in stock, they can be ordered before scheduling your service date.
This letter identifies your vehicle. Presentation of this letter to your dealer will assist their Service personnel in completing the necessary correction to your vehicle in the shortest possible time.
We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products.
Customer Support Department General Motors of Canada Limited
2N06
JL:vt
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
