Engine Lubrication Diagnostic Table
| CONDITION | POSSIBLE CAUSES | CORRECTION |
|---|---|---|
| OIL LEAKS | 1. Gaskets and O-rings. Misaligned or damaged. | 1. Replace as necessary. |
| (a) Loose fasteners, broken or porous metal parts. | (a) Tighten fasteners, Repair or replace metal parts. | |
| 2. Crankshaft rear oil seal. | 2. Replace rear crankshaft oil seal. Refer to SEAL, CRANKSHAFT OIL, REAR, REMOVAL . | |
| 3. Crankshaft rear oil seal surface. Scratched, nicked or grooved. | 3. Polish or replace crankshaft. | |
| 4. Oil pan flange cracked. | 4. Replace oil pan. Refer to PAN, OIL, REMOVAL . | |
| 5. Crankshaft front oil seal. | 5. Replace front crankshaft oil seal. Refer to SEAL, CRANKSHAFT OIL, FRONT, REMOVAL . | |
| 6. Crankshaft front oil seal surface. Scratched, nicked or grooved. | 6. Polish or replace crankshaft. | |
| OIL PRESSURE DROP | 1. Low oil level. | 1. Check and correct oil level. |
| 2. Faulty oil pressure switch. | 2. Replace switch. Refer to SWITCH, OIL PRESSURE, REMOVAL . | |
| 3. Low oil pressure. | 3. Check main bearing clearance. Refer to BEARING(S), CRANKSHAFT, MAIN, STANDARD PROCEDURE . 3. Check rod bearing clearance. Refer to BEARING(S), CONNECTING ROD, STANDARD PROCEDURE . |
|
| 4. Clogged oil filter. | 4. Replace oil filter. Refer to FILTER, ENGINE OIL, REMOVAL . | |
| 5. Worn oil pump. | 5. Replace oil pump. Refer to PUMP, ENGINE OIL, REMOVAL . | |
| 6. Thin or diluted oil. | 6. Change oil and filter. Refer to OIL, STANDARD PROCEDURE . | |
| 7. Excessive bearing clearance. | 7. Replace crankshaft bearings. Refer to BEARING(S), CRANKSHAFT, MAIN, STANDARD PROCEDURE . 7. Replace rod bearings. Refer to BEARING(S), CONNECTING ROD, STANDARD PROCEDURE . |
|
| 8. Oil pump relief valve stuck. | 8. Replace oil pump. Refer to PUMP, ENGINE OIL, REMOVAL . | |
| 9. Oil pump pick-up tube loose, damaged or clogged. | 9. Replace oil pump pick-up. Refer to PICK-UP, OIL PUMP, REMOVAL . | |
| OIL PUMPING AT RINGS; SPARK PLUGS FOULING | 1. Worn or damaged rings. | 1. Hone cylinder bores and replace rings. Refer to RING(S), PISTON, STANDARD PROCEDURE . |
| 2. Carbon in oil ring slots. | 2. Replace rings. Refer to ROD, PISTON AND CONNECTING, REMOVAL . | |
| 3. Worn valve guides. | 3. Replace cylinder heads. Refer to CYLINDER HEAD, REMOVAL . | |
| 4. Leaking valve guide seals. | 4. Replace valve guide seals. Refer to SEAL(S), VALVE GUIDE, REMOVAL . |