ENGINE OIL LEAKS DIAGNOSIS/REPAIR INFORMATION

This bulletin will address the identification of potential oil leak areas, and repair of oil leaks on the GM 2.5L L4 engine.

Oil leaks are sometimes difficult to locate and, therefore, not always repaired the first time.

Two (2) most common means of identifying oil leaks are "the black light method" or "the baby powder method". Prior to attempting either of these two (2) methods, the suspected leak area should be cleaned with a solvent.

Black light kits (Kent Moore Tool No. J28428-A) are available through Kent Moore Tool Division. Included in the kit are detailed instructions on how to use the kit.

Using "the baby powder method", be sure the suspected leak area is clean. Sprinkle baby powder around the suspected leak area. Start the engine allowing it to thoroughly warm up. Observe the baby powder area for any discoloration or wet spots.

Each of the following are potential leak areas and discuss the proper method for repair.

ROCKER ARM COVER

(1) With the rocker arm cover removed, thoroughly clean R.T.V. from rocker arm cover and cylinder head mating surfaces.

(2) Clean sealing surfaces with lacquer thinner or other solvent which will leave mating surfaces dry and free of oil and other foreign material.

(3) Inspect the rocker arm cover and cylinder head mating surfaces for flatness/high spots.

(4) Apply a 5.0mm (3/16") bead of R.T.V. sealer (GM P/N 1052366) to cylinder head being sure that the bead is inside at the bolt hole locations.

(5) Install rocker arm cover within eight (8) minutes to prevent over cure of sealer. Torque all bolts to 10 N.m (7 lb. ft.).

PUSH ROD COVER

(1) With push rod cover removed, clean R.T.V. from cover to cylinder block mating surfaces.

(2) Clean sealing surfaces with lacquer thinner or other solvent which will leave mating surfaces dry and free of oil and other foreign material.

(3) Apply a 5.0mm (3/16") bead of R.T.V. sealer (GM P/N 1052366) to push rod cover sealing surface.

(4) Install push rod cover (within 10 minutes) and torque bolts to 9 N.m (75 lb. in.).

REAR OIL GALLERY PLUG

Rear oil gallery plugs may leak as a result of being cross-threaded, lack of sealer, or not installed deep enough.

When replacing an oil gallery plug, apply pipe sealer to plug threads and torque to 50 N.m (37 lb. ft.).

REAR MAIN OIL SEAL

(1) With all necessary components removed, remove rear main oil seal.

(2) Inspect crankshaft for the following:

Nicks or scratches that may deteriorate seal lip.

Seal lip to crankshaft mating surface for wear (lack of lubrication will enable seal lip to wear the crankshaft).

Poor machining on crankshaft sealing surface.

(3) With new seal thoroughly lubricated with engine oil, install new seal.

OIL PAN GASKET

(1) With oil pan removed, clean oil pan to cylinder block mating surfaces.

(2) Use only oil pan gasket set (P/N 10021749).

(3) Apply a 1/8" bead of R.T.V. sealer (GM P/N 1052366) at gasket split lines.

(4) Install oil pan and torque bolts to 10 N.m (7 lb. ft.).

Whenever possible, locating pins should be used when installing components with R.T.V. to avoid wiping the sealant off the mating surfaces.

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.