| Problem |
Possible Cause |
Remedy/Repair |
| External oil leaks |
- Cylinder head cover RTV sealant broken or improperly seated
- Oil filler cap leaking or missing
- Oil filter gasket broken or improperly seated
- Oil pan side gasket broken, improperly seated or opening in RTV
sealant
- Oil pan front oil seal broken or improperly seated
- Oil pan rear oil seal broken or improperly seated
- Timing case cover oil seal broken or improperly seated
- Excess oil pressure because of restricted PCV valve
- Oil pan drain plug loose or has stripped threads
- Rear oil gallery plug loose
- Rear camshaft plug loose or improperly seated
|
- Replace sealant; inspect cylinder head cover sealant flange and
cylinder head sealant surface for distortion and cracks
- Replace cap
- Replace oil filter
- Replace gasket or repair opening in sealant; inspect oil pan gasket
flange for distortion
- Replace seal; inspect timing case cover and oil pan seal flange for
distortion
- Replace seal; inspect oil pan rear oil seal flange; inspect rear
main bearing cap for cracks, plugged oil return channels, or distortion
in seal groove
- Replace seal
- Replace PCV valve
- Repair as necessary and tighten
- Use appropriate sealant on gallery plug and tighten
- Seat camshaft plug or replace and seal, as necessary
|
| Excessive oil consumption |
- Oil level too high
- Oil with wrong viscosity being used
- PCV valve stuck closed
- Valve stem oil deflectors (or seals) are damaged, missing, or
incorrect type
- Valve stems or valve guides worn
- Poorly fitted or missing valve cover baffles
- Piston rings broken or missing
- Scuffed piston
- Incorrect piston ring gap
- Piston rings sticking or excessively loose in grooves
- Compression rings installed upside down
- Cylinder walls worn, scored, or glazed
- Piston ring gaps not properly staggered
- Excessive main or connecting rod bearing clearance
|
- Drain oil to specified level
- Replace with specified oil
- Replace PCV valve
- Replace valve stem oil deflectors
- Measure stem-to-guide clearance and repair as necessary
- Replace valve cover
- Replace broken or missing rings
- Replace piston
- Measure ring gap, repair as necessary
- Measure ring side clearance, repair as necessary
- Repair as necessary
- Repair as necessary
- Repair as necessary
- Measure bearing clearance, repair as necessary
|
| No oil pressure |
- Low oil level
- Oil pressure gauge, warning lamp or sending unit inaccurate
- Oil pump malfunction
- Oil pressure relief valve sticking
- Oil passages on pressure side of pump obstructed
- Oil pickup screen or tube obstructed
- Loose oil inlet tube
|
- Add oil to correct level
- Replace oil pressure gauge or warning lamp
- Replace oil pump
- Remove and inspect oil pressure relief valve assembly
- Inspect oil passages for obstruction
- Inspect oil pickup for obstruction
- Tighten or seal inlet tube
|
| Low oil pressure |
- Low oil level
- Inaccurate gauge, warning lamp or sending unit
- Oil excessively thin because of dilution, poor quality, or improper
grade
- Excessive oil temperature
- Oil pressure relief spring weak or sticking
- Oil inlet tube and screen assembly has restriction or air leak
- Excessive oil pump clearance
- Excessive main, rod, or camshaft bearing clearance
|
- Add oil to correct level
- Replace oil pressure gauge or warning lamp
- Drain and refill crankcase with recommended oil
- Correct cause of overheating engine
- Remove and inspect oil pressure relief valve assembly
- Remove and inspect oil inlet tube and screen assembly. (Fill inlet
tube with lacquer thinner to locate leaks.)
- Measure clearances
- Measure bearing clearances, repair as necessary
|
High oil pressure
|
- Improper oil viscosity
- Oil pressure gauge or sending unit inaccurate
- Oil pressure relief valve sticking closed
|
- Drain and refill crankcase with correct viscosity oil
- Replace oil pressure gauge
- Remove and inspect oil pressure relief valve assembly
|
| Main bearing noise |
- Insufficient oil supply
- Main bearing clearance excessive
- Bearing insert missing
- Crankshaft end-play excessive
- Improperly tightened main bearing cap bolts
- Loose flywheel or drive plate
- Loose or damaged vibration damper
|
- Inspect for low oil level and low oil pressure
- Measure main bearing clearance, repair as necessary
- Replace missing insert
- Measure end-play, repair as necessary
- Tighten bolts with specified torque
- Tighten flywheel or drive plate attaching bolts
- Repair as necessary
|
| Connecting rod bearing noise |
- Insufficient oil supply
- Carbon build-up on piston
- Bearing clearance excessive or bearing missing
- Crankshaft connecting rod journal out-of-round
- Misaligned connecting rod or cap
- Connecting rod bolts tightened improperly
|
- Inspect for low oil level and low oil pressure
- Remove carbon from piston crown
- Measure clearance, repair as necessary
- Measure journal dimensions, repair or replace as necessary
- Repair as necessary
- Tighten bolts with specified torque
|
| Piston noise |
- Piston-to-cylinder wall clearance excessive (scuffed piston)
- Cylinder walls excessively tapered or out-of-round
- Piston ring broken
- Loose or seized piston pin
- Connecting rods misaligned
- Piston ring side clearance excessively loose or tight
- Carbon build-up on piston is excessive
|
- Measure clearance and examine piston
- Measure cylinder wall dimensions re-bore cylinder
- Replace all rings on piston
- Measure piston-to-pin clearance, repair as necessary
- Measure rod alignment, straighten or replace
- Measure ring side clearance, repair as necessary
- Remove carbon from piston
|
| Valve actuating component noise |
- Insufficient oil supply
- Rocker arms or pivots worn
- Foreign objects or chips in hydraulic tappets
- Excessive tappet leak-down
- Tappet face worn
- Broken or cocked valve springs
- Stem-to-guide clearance excessive
- Valve bent
- Loose rocker arms
- Valve seat run-out excessive
- Missing valve lock
- Excessive engine oil
|
- Check for:
(a) Low oil level
(b) Low oil pressure
(c) Wrong
hydraulic tappets
(d) Restricted oil gallery
(e) Excessive tappet
to bore clearance
- Replace worn rocker arms or pivots
- Clean tappets
- Replace valve tappet
- Replace tappet; inspect corresponding cam lobe for wear
- Properly seat cocked springs; replace broken springs
- Measure stem-to-guide clearance, repair as required
- Replace valve
- Check and repair as necessary
- Regrind valve seat/valves
- Install valve lock
- Correct oil level
|
