BYPASS ENGINE COOLANT KIT TEMP GAGE/LIGHT CYCLING

VEHICLES AFFECTED: 1985 'C' Series with 3.8L MFI Engine (LN3) 1984-1985 'A' Series with 3.8L MFI Engine (LN3)

A new service kit to revise 3.8L MFI engines built prior to December, 1984 is now available. This additional bypass supplements that already provided through the heater. This kit must be used in conjunction with the new style water pump and gasket in kit, Part Number 25525147, and three (3) tablets (tabs) of 3634621 (6 tabs per package) cooling system supplement or a locally available equivalent such as 'Bars Leak'. The bypass kit, Part Number 25526634, contains an adapter, connector, pipe assembly, hose clamps (2), instruction sheet, 195 degree thermostat, and thermostat gasket.

Several performance changes are provided by installing this kit including: reduced engine coolant temperature cycling; reduced temperature gauge cycling or an intermittent hot light; reduced possibility of trapped air in the engine; and if the 195 degree thermostat assembly included in the kit is installed, increased heater air output temperature about 10 degrees F. The thermostat must be changed if not previously changed. Three tabs of cooling system supplement or equivalent must be added before reinstalling radiator cap to assure protection is maintained at original factory levels.

A bypass kit is being developed for the 'N' Series 3.0L MFI engine (LN7).

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.