Since it is sometimes difficult to determine the source of an oil leak in the rear seal area of the engine, a more involved inspection is necessary. The following steps should be followed to help pinpoint the source of the leak.
If the leakage occurs at the crankshaft rear oil seal area:
1. Disconnect the battery.
2. Raise and support the vehicle.
3. Remove torque converter or clutch housing inspection cover.
4. Using a black light and inspect the rear of the engine block for evidence of oil.
Circular spray pattern on the rear of the engine block generally indicates:
– Rear crankshaft oil seal
– Damaged crankshaft
Oil running straight down the back of the engine block generally indicates:
– Porous engine block
– Camshaft core hole plug
– Oil gallery pipe plug
– Oil pan gasket
5. Oil pan gasket
If no leaks are detected, pressurize the crankcase as outlined in the AIR LEAK DETECTION TEST METHOD.
CAUTION: Do not subject the engine assembly to more than 20.6 kPa (3 PSI) of test pressure.
6. If the leak is not detected, very slowly turn the crankshaft and watch for leakage. If a leak is detected between the crankshaft and crankshaft oil seal while slowly turning the crankshaft, it is possible the crankshaft seal surface is damaged. The seal area on the crankshaft could have minor nicks or scratches that can be polished out with emery cloth.
CAUTION: Use extreme caution when crankshaft polishing is necessary to remove minor nicks and scratches. The crankshaft seal flange is machined specifically to complement the function of the rear oil seal.
7. For bubbles that remain steady with shaft rotation, no further inspection can be done until disassembled.
