GM Service Manual Online
For 1990-2009 cars only

COOLING SYSTEM SEALANT ADDED IN PRODUCTION

MODELS: 1988 C/K, R/V, S/T, G AND M MODELS

All 1988 light duty trucks built after June 1, 1988 are produced with a cooling system sealant to stop minor leaks in the cooling system. The addition of the sealant to the cooling system may cause the coolant to appear to have a tan or white powdery residue in the radiator, and may cause a film to appear around the inside of the coolant recovery reservoir. These conditions are normal and the cooling system should not be flushed to remove the sealant.

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.