ANALYSIS OF ENGINES WITH INTERNAL SLUDGE ACCUMULATION

MODEL AND YEAR: ALL CHEVROLET ENGINES

When disassembling engines, especially at higher mileages, an accumulation of oil sludge in the crankcase, lifter gallery and/or valve train area is occasionally seen. That condition may result from a lack of maintenance where, for example, the oil/filter/coolant change recommendations are not followed. Such sludging can also be the result of coolant leakage into the oil.

It is therefore, recommended that a careful observation of such engines be made to locate and correct any potential coolant-to-oil leaks that might occur in areas such as cylinder head gaskets, inlet manifold side gaskets or loose/broken cylinder head bolts.

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.