EXHAUST SYSTEM WATER SLUSH SPLASH SHIELD-P/N

SUBJECT: EXHAUST SYSTEM WATER/SLUSH SPLASH SHIELD: NEW PART NUMBER AVAILABLE (Revised to correct illustrations)

VEHICLES AFFECTED: 1985-90 'C' MODELS, 1986-90 'H' MODELS -----------------------------------------------------------------------------

On the above vehicles, it is possible to have a condition of the exhaust pipe contacting the intermediate heat shield, which is located between the exhaust pipe and the floor panel. This condition could occur when water or slush is splashed onto the underside of the exhaust pipe. The rapid cooling and resultant contraction may cause the pipe to bow upwards making contact with the shield above it.

It is possible that the knocking noise could be transmitted to the engine through the exhaust pipe. This could be picked up by the ESC knock sensor, which in turn, would signal the ECM (by lack of voltage), causing it to respond with retarded ignition timing, thinking the engine has a detonation condition.

CORRECTION FOR-1985-1988 VEHICLES

1. Order shield from CANSPO P/N #25533711 which consists of two pieces.

2. Install the shields with three stainless steel clamps and the existing front bracket as shown in Figure 1.

CORRECTION FOR 1989-1990 VEHICLES

1. Order shield from CANSPO P/N #25533711.

2. Notch both the front and rear halves of the shield as shown in Fig. 2, to clear the cross brace welded to the exhaust pipe. Install the shields with three stainless steel clamps and the existing front bracket as shown in Fig. 2.

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.