RUSTY COOLANT COOLING SYSTEM MAINTENANCE

Engine coolant may become rusty and discolored when used beyond the time/mileage intervals specified in the owner maintenance schedule.

This rust or discoloration is an indication that the inhibitors in the coolant have become ineffective. Extended use of coolant of this type may result in heater and/or radiator corrosion, as well as freeze plug and head gasket deterioration.

Whenever service is performed which requires that the coolant be drained on a vehicle which is past the time/ mileage interval specified, this fact should be brought to the attention of the owner. Flushing of the cooling system and new coolant should be recommended. Any time the coolant has an obvious rusty appearance, the owner should be advised and system flushing plus new coolant recommended. Coolant that meets General Motors Specifications 1825-M must be used.

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.