CAMPAIGN: PREMATURE PISTON FAILURE
SUBJECT: PREMATURE PISTON FAILURE
Models: 1990-1995 GMC Medium Duty C5H, C6H, and C7H Trucks with 6.OL (RPO LSO) Engines and Automatic Transmissions
TO: ALL GENERAL MOTORS DEALERS
General Motors of Canada Limited has determined that CERTAIN 1990-1995 GMC C5H, C6H, and C7H Trucks equipped with 6.OL engine (RPO LSO - VIN Code "P") and automatic transmission may experience premature piston failures due to pre-ignition spark plug firing.
To correct this condition, it will be necessary to install a new distributor cap, new distributor rotor, new spark plug wires and new spark plug wire heat shields. On affected 1995 vehicle, only a new distributor rotor is required.
VEHICLES INVOLVED:
Involved are CERTAIN 1990-1995 GMC C5H, C6H, and C7H Trucks equipped with 6.OL engines and automatic transmissions, and built within the following VIN breakpoints:
Year Make Model From Through
1990 GMC C6H, C7H SOP EOP 1991 GMC C5H, C6H, C7H SOP EOP 1992 GMC C6H, C7H SOP EOP 1993 GMC C6H, C7H SOP EOP 1994 GMC C6H, C7H SOP EOP 1995 GMC C6H, C7H SOP SJ503937
NOTE: PLEASE CHECK DCS SCREEN 4S OR YOUR V.I.N. LISTING BEFORE PERFORMING CAMPAIGN TO ENSURE THAT THE VEHICLE IS AFFECTED. ONLY AFFECTED VIN'S WELL BE PAID.
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:
All unsold new vehicles in dealer's possession and subject to this campaign MUST be held and inspected/repaired per the Service Procedure of this Campaign Bulletin before owners take possession of these vehicles.
Dealers are to perform this campaign on all involved vehicles at no charge to owners, regardless of kilometers traveled, age of vehicle, or ownership, from this time forward.
Owners of vehicles recently sold from your new vehicle inventory with no owner information indicated on the dealer listing, are to be contacted by the dealer, and arrangements made to make the required correction according to instructions contained in this bulletin. This could be done by mailing to such owners a copy of the owner letter accompanying this bulletin. Campaign follow-up cards should not be used for this purpose, since the owner may not as yet have received the notification letter
In summary, whenever a vehicle subject to this campaign is taken into your new or used vehicle inventory, or is in your dealership for service in the future, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle.
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 (see copy of owner letter included with this bulletin). 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 ---------------------------------------------------------------------------- 12528918 Ignition Kit, Engine Pre-Ignition Repair 1 (1990-1994) 10477219 Rotor - Distributor 1 (1995 only))
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 distributor cap and rotor, spark plug .7 wires and heat shields 3A Replace only distributor rotor (1995 model year) .4
Time allowance includes 0.1 hour for dealer administrative detail associated with this campaign. Parts credit will be based on dealer net plus 30% for 1990-1993 models and 40% for 1994-1995 models to cover parts handling.
SERVICE PROCEDURE:
MAKE SURE THE IGNITION SWITCH IS "OFF." --------------------------------------- 1990-1994 Models Only --------------------- 1. Remove air cleaner and hoses.
2. Remove spark plug wires and shields from spark plugs and routing clips. It may be easiest to pull the shields out with the wire boots still inserted.
3. Remove distributor cap and spark plug wire assembly, leaving the spark plug wires attached to the cap.
4. Remove the distributor rotor.
5. Install new distributor rotor from kit
6. Install new distributor cap from kit
7. Install new spark plug wire harnesses and ignition coil wire from the kit, using the old cap with old wires as a guide. Also refer to Figures 1 through 3.
Note: Special care should be taken when installing the spark plug wire boots to ensure the metal terminal within the boot is fully seated on the spark plug terminal and the boot has not moved on the wire. Although the shields are pre-installed on the boots, make sure the boots are fully into the shields after connection to the spark plugs.
8. Install air cleaner and hoses.
9. Install Campaign Identification Label.
1995 Models Only
1. Remove air cleaner and hoses.
2. Remove distributor cap, leaving spark plug wires attached.
3. Remove distributor rotor.
4. Install new distributor rotor.
5. Reinstall distributor cap.
6. Reinstall air cleaner and hoses.
7. Install 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.
Dear General Motors Customer
General Motors of Canada Limited has determined that CERTAIN 1990-1995 GMC TopKicks equipped with 6.OL fuel-injected gas engine and automatic transmission may experience premature piston failures due to pre-ignition spark plug firing.
To correct this condition, it is necessary to install a new distributor cap, new distributor rotor, new spark plug wires and new spark plug wire heat shields on most trucks. On 1995 model year trucks only, a new distributor rotor is all that is required.
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
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.
