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DIAGNOSIS AND TESTING—ENGINE DIAGNOSIS - LUBRICATION CONDITION POSSIBLE CAUSES CORRECTION OIL LEAKS 1. Gaskets and O-Rings. 1. (a) Misaligned or damaged. (a) Replace as necessary. (b) Loose fasteners, broken or (b) Tighten fasteners, Repair or 2. Crankshaft rear seal 2. Replace as necessary. 3. Crankshaft seal flange. 3. Polish or replace crankshaft. 4. Oil pan flange cracked. 4. Replace oil pan. 5. Timing chain cover seal, 5. Replace seal. 6. Scratched or damaged vibration 6. Polish or replace damper. OIL PRESSURE DROP 1. Low oil level. 1. Check and correct oil level. 2. Faulty oil pressure sending unit. 2. Replace sending unit. 3. Low oil pressure. 3. Check pump and bearing 4. Clogged oil filter. 4. Replace oil filter. 5. Worn oil pump. 5. Replace as necessary. 6. Thin or diluted oil. 6. Change oil and filter. 7. Excessive bearing clearance. 7. Replace as necessary. 8. Oil pump relief valve stuck. 8. Clean or replace relief valve. 9. Oil pump suction tube loose or 9. Replace as necessary. OIL PUMPING AT RINGS; SPARK PLUGS FOULING 1. Worn or damaged rings. 1. Hone cylinder bores and replace 2. Carbon in oil ring slots. 2. Replace rings. 3. Incorrect ring size installed. 3. Replace rings. 4. Worn valve guides. 4. Ream guides and replace valves. 5. Leaking intake gasket. 5. Replace intake gaskets. 6. Leaking valve guide seals. 6. Replace valve guide seals. DIAGNOSIS AND TESTING—CYLINDER The results of a cylinder compression pressure test can be utilized to diagnose several engine malfunc- Ensure the battery is completely charged and the engine starter motor is in good operating condition. (1) Clean the spark plug recesses with compressed air. (2) Remove the spark plugs (Refer to 8 - ELEC- TRICAL/IGNITION CONTROL/SPARK PLUG - REMOVAL). (3) Secure the throttle in the wide-open position. the engine with the engine starter motor for three (6) Record the compression pressure on the third revolution. Continue the test for the remaining cylin- 9 - 8 ENGINE 2.5L AN ENGINE 2.5L (Continued) |