| VALVETRAIN NOISE | 1. High or low oil level in crankcase. | 1. Check and correct engine oil level. |
| 2. Thin or diluted oil. | 2. Change oil to correct viscosity. |
| 3. Thick oil | 3. (a) Change engine oil and filter. |
| (b) Run engine to operating temperature. |
| (c) Change engine oil and filter again. |
| 4. Low oil pressure. | 4. Check and correct engine oil level. |
| 5. Worn cam lobe. | 5. Install new camshaft. |
| 6. Worn tappet bucket. | 6. Install new select fit tappet bucket. |
| 7. Worn valve guides. | 7. Replace cylinder head. |
| 8. Excessive runout of valve seats on valve faces. | 8. Grind valve seats and replace valves. |
| CONNECTING ROD NOISE | 1. Insufficient oil supply. | 1. Check engine oil level. |
| 2. Low oil pressure. | 2. Check engine oil level. Inspect oil pump relief valve and spring. |
| 3. Thin or diluted oil. | 3. Change oil to correct viscosity. |
| 4. Thick oil | 4. (a) Change engine oil and filter. |
| (b) Run engine to operating temperature. |
| (c) Change engine oil and filter again. |
| 5. Excessive bearing clearance. | 5. Measure bearings for correct clearance. Repair as necessary. |
| 6. Connecting rod journal out-of-round. | 6. Replace crankshaft or grind surface. |
| 7. Connecting rod out-of-round. | 7. Replace connecting rod. |
| 8. Misaligned connecting rods. | 8. Replace bent connecting rods. |
| MAIN BEARING NOISE | 1. Insufficient oil supply. | 1. Check engine oil level. |
| 2. Low oil pressure. | 2. Check engine oil level. Inspect oil pump relief valve and spring. |
| 3. Thin or diluted oil. | 3. Change oil to correct viscosity. |
| 4. Thick oil | 4. (a) Change engine oil and filter. |
| (b) Run engine to operating temperature. |
| (c) Change engine oil and filter again. |
| 5. Excessive bearing clearance. | 5. Measure bearings for correct clearance. Repair as necessary. |
| 6. Excessive end play. | 6. Check thrust bearing for wear on flanges. |
| 7. Crankshaft journal out-of-round or worn. | 7. Replace crankshaft or grind journals. |
| 8. Loose flywheel or torque converter. | 8. Tighten to correct torque. |
| OIL PRESSURE DROP | 1. Low oil level. | 1. Check engine oil level. |
| 2. Faulty oil pressure sending unit. | 2. Install new sending unit. |
| 3. Low oil pressure. | 3. Check sending unit and main bearing oil clearance. |
| 4. Clogged oil filter. | 4. Install new oil filter. |
| 5. Worn parts in oil pump. | 5. Replace balance shaft module. |
| 6. Thin or diluted oil. | 6. Change oil to correct viscosity. |
| 7. Oil pump relief valve stuck. | 7. Remove valve and inspect, clean, or replace. |
| 9. Excessive bearing clearance. | 9. Measure bearings for correct clearance. |
| OIL LEAKS | 1. Misaligned or deteriorated gaskets. | 1. Replace gasket(s). |
| 2. Loose fastener, broken or porous metal part. | 2. Tighten, repair or replace the part. |
| 3. Misaligned or deteriorated cup or threaded plug. | 3. Replace as necessary. |
| OIL CONSUMPTION OR SPARK PLUGS FOULED | 1. PCV system malfunction. | 1. Check system and repair as necessary. Refer to VALVE, Positive Crankcase Ventilation (PCV) , Diagnosis and Testing . |
| 2. Worn, scuffed or broken rings. | 2. Hone cylinder bores. Install new rings. |
| 3. Carbon in oil ring slots. | 3. Install new rings. |
| 4. Rings fitted too tightly in grooves. | 4. Remove rings and check grooves. If groove is not proper width, replace piston. |
| 5. Worn valve guide(s). | 5. Replace cylinder head. |
| 6. Valve stem seal(s) worn or damaged. | 6. Replace seal(s). |
