Chrysler 1998 Voyager Service Manual page 1062

9 - 12 ENGINE
DIAGNOSIS AND TESTING (Continued)
ENGINE DIAGNOSIS—MECHANICAL
CONDITION
NOISY VALVES
CONNECTING ROD NOISE
MAIN BEARING NOISE
OIL PRESSURE DROP
POSSIBLE CAUSES
1. High or low oil level in
crankcase.
2. Thin or diluted oil.
3. Low oil pressure.
4. Dirt in tappets/lash adjusters.
5. Worn rocker arms.
6. Worn tappets/lash adjusters.
7. Worn valve guides.
8. Excessive runout of valve seats
on valve faces.
9. Missing adjuster pivot.
1. Insuffient oil supply.
2. Low oil pressure.
3. Thin or diluted oil.
4. Excessive bearing clearance.
5. Connecting rod journal
out-of-round.
6. Misaligned connecting rods.
1. Insufficient oil supply.
2. Low oil pressure.
3. Thin or diluted oil.
4. Excessive bearing clearance.
5. Excessive end play.
6. Crankshaft journal out-of-round
or worn.
7. Loose flywheel or torque
converter.
1. Low oil level.
2. Faulty oil pressure sending unit.
3. Low oil pressure.
4. Clogged oil filter.
5. Worn parts in oil pump.
6. Thin or diluted oil.
7. Excessive bearing clearance.
8. Oil pump relief valve stuck.
9. Oil pump suction tube loose.
10. Oil pump cover warped or
cracked.
CORRECTION
1. Check for correct oil level.
2. Change oil to correct viscosity.
3. Check engine oil level.
4. Replace rocker arm/hydraulic
lash adjuster assembly.
5. Inspect oil supply to rocker arms.
6. Install new rocker arm/hydraulic
lash adjuster assembly.
7. Ream and install new valves with
oversize stems.
8. Grind valve seats and valves.
9. Replace rocker arm/hydraulic
lash adjuster assembly.
1. Check engine oil level.
2. Check engine oil level. Inspect oil
pump relief valve and spring.
3. Change oil to correct viscosity.
4. Measure bearings for correct
clearance. Repair as necessary.
5. Replace crankshaft or grind
surface.
6. Replace bent connecting rods.
1. Check engine oil level.
2. Check engine oil level. Inspect oil
pump relief valve and spring.
3. Change oil to correct viscosity.
4. Measure bearings for correct
clearance. Repair as necessary.
5. Check thrust bearing for wear on
flanges.
6. Replace crankshaft or grind
journals.
7. Tighten to correct torque.
1. Check engine oil level.
2. Install new sending unit.
3. Check sending unit and main
bearing oil clearance.
4. Install new oil filter.
5. Replace worn parts or pump.
6. Change oil to correct viscosity.
7. Measure bearings for correct
clearance.
8. Remove valve and inspect, clean,
or replace.
9. Remove oil pan and install new
tube or clean, if necessary.
10. Install new oil pump.
NS