CAMPAIGN: FUEL INJECTION PUMP HOUSING EROSION
SUBJECT: FUEL INJECTION PUMP HOUSING EROSION
MODELS: 1992-93 W5-7 GMC FORWARD AND CHEVROLET TILTMASTER W/6.5L (6BG1TC) DIESEL ENGINES
General Motors has learned that the fuel injection pump housing may erode on certain 1992-93 W5-7 GMC Forward and Chevrolet Tiltmasters equipped with 6.5L (6BG1TC) Diesel Engines. The erosion condition could eventually allow diesel fuel to leak into the engine crankcase causing oil dilution which could lead to engine failure. Analysis has shown that the pump housing erosion condition is the result of cavitation in the injection pump caused by positive to negative pressure fluctuations. To correct this condition, the location of the fuel supply line on the transfer pump will be switched from the outboard Port "A" (Figure 3) to the inboard Port "B" (Figure 3).
VEHICLES INVOLVED
Involved are CERTAIN 1992-93 W5-7 GMC Forward and Chevrolet Tiltmaster vehicles built within the following VIN breakpoints:
MODEL YEAR MODEL FROM THROUGH
1992 W5 N3000012 N3002274 W6 N3100012 N3100842 W7 N3200010 N3202222 W7HV N3300003 N3300560 W7T N3400002 N3400008 1993 W5 P3000002 P3000060 W6 P3100410 P3100438 W7 P3200004 P3200077
The specific vehicles involved in this campaign have been identified by Vehicle Identification Number Computer Listings. These listings are furnished to all involved dealers with the campaign bulletin.
DEALER CAMPAIGN RESPONSIBILITY
Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward. Dealers are to correct all affected vehicles in new and used vehicle stock prior to their sale.
Whenever a vehicle subject to this campaign is taken into your new or used vehicle inventory, or it is in your dealership for service in the future, you should take the steps necessary to ensure the campaign correction has been made before reselling 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 correction according to instructions contained in this bulletin.
If the name and address of the owner of an involved vehicle was unavailable to GMC Truck Division at the time of campaign initiation, the dealer must determine the owner's name and address from the dealership sales records. Please provide this information directly on the second copy of the listing next to the applicable VIN so that our records may be updated and the appropriate notification mailed to the owner. This second copy should then be submitted to the address listed below in the previously supplied yellow campaign envelopes.
GMC Truck Division General Motors Corporation 101 Union Street Plymouth, Michigan 48170
OWNER NOTIFICATION
Owners will be notified of this campaign on their vehicles by GMC Truck Division (see copy of owner lefter included with this bulletin). A listing of owner names and addresses has been furnished to the involved dealers to enable dealers to follow up with owners involved in this campaign. This listing may
Dear General Motors Truck Owner:
General Motors has learned that the the fuel injection pump housing may erode on certain 1992-93 W5-7 GMC Forward and Chevrolet Tiltmasters equipped with 6.5L Diesei Engines. The erosion condition could eventually allow diesel fuel to leak into the engine crankcase causing oil dilution which could lead to engine failure. Analysis has shown that the pump housing erosion condition is the result of cavitation in the injection pump caused by positive to negative pressure fluctuations.
To correct this condition, the fuel supply line will be relocated on the transfer pump. This change will insure that the pump pressure will remain positive, increasing pump durability and reliability without affecting engine performance. This service will be completed for you at no charge.
Instructions for making this correction have been sent to your GM dealer. Please contact your dealer as soon as possible to arrange a service date. Ask your dealer if you wish to know how much time will be needed to schedule, process and repair your vehicle.
The enclosed postage paid owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction to your vehicle in the shortest possible time. If you have sold or traded your vehicle, please furnish us the complete name and address of the person to whom you sold or traded your vehicle and return the card to us.
We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products.
GMC TRUCK DIVISION GENERAL MOTORS CORPORATION
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.
