WHITE SMOKE FROM EXHAUST AFTER EXTENDED IDLE

MODELS: 1986 AND 1987 S/T TRUCKS WITH 2.8L V6 ENGINE (VIN CODE R) AND FEDERAL EMISSIONS

THIS BULLETIN CANCELS AND SUPERSEDES TRUCK SERVICE BULLETIN 86-T-131 (GROUP 6F) DATED JANUARY, 1987, ALL COPIES OF WHICH SHOULD BE DESTROYED.

Some 1986 and 1987 S/T trucks with 2.8L V6 engines and Federal Emissions may exhibit a blue/white smoke from the tailpipe after an extended idle.

To repair this condition, check the truck for loss of coolant or excessive use of oil and repair if necessary.

If engine checks O.K. (no oil or coolant loss), replace the PROM, using the following chart for application and part numbers. Use the service procedure in Section 6E-Engine Emissions and Drivability of the appropriate service manual.

Service PROM Application *

Model Service Year Model Transmission Axle PROM ----- ---- ------------ ---- -------- 86/87 S/T M4 All 1228541

86/87 S/T M5 3.73 1228542 3.42

86/87 S/T M5 4.11 1228543

86/87 A A4 All 1228544

86 T A4 3.73 1228545

87 T A4 3.73 1228544

86/87 T A4 4.11 1228545

* 2.8L 1986/87 Federal Emissions applications only.

Use applicable labor time and operation numbers.

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.