DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - MECHANICAL
CONDITION POSSIBLE CAUSES CORRECTION
NOISY VALVES 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 oil and filter.
(b.) Run engine to operating
temperature.
(c.) Change oil and filter again.
4. Low oil pressure. 4. Check and correct engine oil
level.
5. Dirt in tappets/lash adjusters. 5. Replace rocker arm/hydraulic
lash adjuster assembly.
6. Worn rocker arms. 6. Inspect oil supply to rocker arms.
7. Worn tappets/lash adjusters. 7. Install new rocker arm/hydraulic
lash adjuster assembly.
8. Worn valve guides. 8. Ream guides and install new
valves with oversize stems.
9. Excessive runout of valve seats
on valve faces.
9. Grind valve seats and valves.
10. Missing adjuster pivot. 10. Replace rocker arm/hydraulic
lash adjuster assembly.
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 3. (a.) Change oil and filter.
(b.) Run engine to operating
temperature.
(c.) Change 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. Misaligned connecting rods. 7. Replace bent connecting rods.
9 - 8 ENGINE 2.7L LH
ENGINE 2.7L (Continued)