IGNITION DISTRIBUTOR ASSY. USE (UPDATED INFORMATION)

SUBJECT: IGNITION DISTRIBUTOR ASSEMBLY USAGE (INFORMATION UPDATE)

VEHICLES AFFECTED: 1992 MEDIUM DUTY TRUCK WITH 6.0/7.OL GAS ENGINE (VIN CODE M,P)

THIS BULLETIN IS BEING REVISED TO ADD ADDITIONAL INFORMATION ABOUT ENHANCEMENTS MADE TO THE NEW DISTRIBUTOR ASSEMBLY, TO ADD RPO CODES AND TO INCLUDE ART.

There have been several changes to the production distributor assembly in 1992 medium duty trucks with 6.0/7.0L gas engines (Vin codes P/M, RPO Codes LS0/LR0). Consequently, there are two different colour ignition distributor caps.

All 1992 medium duty trucks, with 6.0/7.0L engines built from the start of production to March 3, 1992, were produced with WHITE distributor caps (P/N 10474757). The white cap had all-aluminum terminals for reduced corrosion.

An additional product improvement went into production at the Tonawanda Engine Plant on March 3, 1992, when a new distributor assembly was installed on all 1992 6.0L and 7.0L engines (Engine serial numbers T0303---- and greater). This new assembly included coated components for enhanced corrosion protection. Now, it also has a BLACK distributor cap (P/N 10475118) with the same updated aluminum terminals. This was strictly a colour change to the cap to return it to its original colour.

The new corrosion resistant coating has been included on the mainshaft assembly, pick-up coil, pole piece, and pick-up coil retainer. The rotor also has a new stainless rotor spring contact for improved durability.

Note: It is possible to determine the vintage of a black distributor cap assembly by:

A. Checking the engine serial number located on the engine block just in front of the right cylinder head. If the number is greater than T0303 ---- and it is a 1992 vehicle, the latest distributor is installed.

B. Pull one plug wire on the cap and check for a vent hole (see Figure 1). The latest distributor will NOT have vents.

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.