Engine Mechanical Diagnostic Table

CONDITION	POSSIBLE CAUSES	CORRECTIONS
NOISY VALVES	1. High or low oil level in crankcase	1. Refer to CAPACITIES AND RECOMMENDED FLUIDS .
	2. Thin or diluted oil	2. Change oil and filter.
	3. Low oil pressure	3. Check oil pump, if Ok, check rod and main bearings for excessive wear.
	4. Spongy and/or stuck collapsed lash adjusters	4. Refer to HYDRAULIC LASH ADJUSTER, DIAGNOSIS AND TESTING .
	5. Dirt in lash adjusters	4. Replace as necessary.
	6. Worn rocker arms	5. Replace as necessary.
	7. Worn lash adjusters	6. Replace as necessary.
	8. Worn valve guides	7. Inspect the valve guides for wear, cracks or looseness. If either condition exists, replace the cylinder head. Refer to CYLINDER HEAD ASSEMBLY, REMOVAL AND INSTALLATION .
	9. Excessive runout of valve seats on valve faces	8. Refer to REFACING INTAKE AND EXHAUST VALVES .
CONNECTING ROD NOISE	1. Insufficient oil supply	1. Refer to ENGINE OIL AND FILTER CHANGE .
	2. Low oil pressure	2. Check oil pump, if OK, check rod and main bearings for excessive wear.
	3. Thin or diluted oil	3. Change oil and filter.
	4. Excessive bearing clearance	4. Replace as necessary.
	5. Connecting rod journal out-of-round	5. Service or replace crankshaft.
	6. Misaligned connecting rods	6. Replace bent connecting rods.
MAIN BEARING NOISE	1. Insufficient oil supply	1. Refer to ENGINE OIL AND FILTER CHANGE .
	2. Low oil pressure	2. Check oil pump, if OK, check rod and main bearings for excessive wear.
	3. Thin or diluted oil	3. Change oil and filter.
	4. Excessive bearing clearance	4. Replace as necessary.
	5. Excessive end play	5. Check thrust washers for wear.
	6. Crankshaft journal out of round	6. Service or replace crankshaft.
	7. Loose flywheel or torque converter	7. Tighten to correct torque.