Symption |
Suspect area |
Remedy |
Engine misfire with abnormal internal lower engine noises. |
Worn crankshaft bearings
Loose or improperly engine filwheel |
Replace the crankshaft and bearings as required.
Repair or replace the flywheel as required. |
Worn piston rings
(Oil consumption may or may not cause the engine to misfire.) |
Inspect the cylinder for a loss of compression.
Repair or replace as required. |
Worn crankshaft thrust bearings |
Replace the crankshaft and bearings as required |
Engine misfire with abnormal valve train noise. |
Stuck valves.
(Carbon buidup on the valve stem) |
Repair or replace as required |
Excessive worn or mis-aligned timing chain |
Replace the timing chain and sprocket as required. |
Worn camshaft lobes. |
Replace the camshaft and valve lifters. |
Engine misfire with coolant consumption |
• |
Faulty cylinder head gasket or other damage to the cylinder head and engine block cooling system.
|
• |
Coolant consumption may or may not cause the engine to overheat.
|
|
• |
Inspect the cylinder head and engine block for damage to the coolant passages and/or a faulty head gasket.
|
• |
Repair or replace as required.
|
|
Engine misfire with excessive oil consumption |
Worn valves, guides and/or valve stem oil seals. |
Repair or replace as required. |
Worn piston rings.
(Oil consumption may or may not cause the engine to misfire) |
• |
Inspect the cylinder for a loss of compression.
|
• |
Repair or replace as required.
|
|
Engine noise on start-up, but only lasting a few seconds. |
Incorrect oil viscosity |
• |
Install the correct viscosity oil.
|
|
Worn crankshaft thrust bearing. |
• |
Inspect the thrust bearing and crankshaft.
|
• |
Repair or replace as required.
|
|
Upper engine noise, regardless of engine speed. |
Low oil pressure |
Repair or replace as required. |
Broken valve spring. |
Replace the valve spring. |
Worn or dirty valve lifters. |
Replace the valve lifters. |
Stetched or broken timing chain and/or damaged sprocket teeth. |
Replace the timing chain and sprockets. |
Worn timing chain tensioner, if applicable. |
Replace the timing chain tensioner as required. |
Worn camshaft lobes. |
• |
Inspect the camshaft lobes.
|
• |
Replace the timing camshaft and valve lifters as required.
|
|
Worn valve guides or valve stems. |
Inspect the valves and valve guides, then repair or replace as required. |
Stuck valves. (Carbon on the valve stem or valve seat may cause the valve to stay open. |
Inspect the valves and valve guides, then repair or replace as required. |
Worn drive belt, idler, tensioner and bearing. |
Replace as required |
Lower engine noise, regardless of engine speed |
Low oil pressure |
Repair or required. |
Loose or damaged flywheel. |
Repair or replace the flywheel. |
Damaged oil pan, contacting the oil pump screen. |
• |
Inspect the oil pump screen.
|
• |
Repair or replace as required.
|
|
Oil pump screen loose, damaged or restricted. |
• |
Inspect the oil pump screen.
|
• |
Repair or replace as required.
|
|
Excessive piston-to-cylinder bore clearance. |
• |
Inspect the piston, piston pin and cylinder bore.
|
• |
Repair or replace as required.
|
|
Excessive piston pin-to-piston clearance |
• |
Inspect the piston, piston pin and the connecting rod.
|
• |
Repair or replace as required.
|
|
Excessive connecting rod bearing clearance |
Inspect the following components and repair or replace as required.
• |
The connecting rod bearings.
|
• |
The crankshaft pin journals.
|
|
Excessive crankshaft bearing clearance |
Inspect the following components, and repair or replace as required.
• |
The crankshaft bearings.
|
• |
The crankshaft main journals.
|
|
Incorrect piston, piston pin and connecting rod installation |
• |
Verify the piston pins and connecting rods are installed correctly.
|
|
Engine noise under load |
Low oil pressure |
Repair or replace as required. |
Excessive connecting rod bearing clearance |
Inspect the following components and repair or replace as required :
• |
The connecting rod bearings.
|
|
Excessive crankshaft bearing clearance |
Inspect the following components, and repair or replace as required.
• |
The crankshaft bearings.
|
• |
The crankshaft main journals.
|
|
Engine will not crank-crankshaft will not rotate |
Hydraulically locked cylinder
• |
Coolant/antifreeze in cylinder.
|
|
1) |
Remove spark plugs and check for fluid.
|
2) |
Inspect for broken head gasket.
|
3) |
Inspect for cracked engine block or cylinder head.
|
4) |
Inspect for a sticking fuel injector and/or leaking fuel regulator.
|
|
Broken timing chain and/or timing chain and/or timing chain gears. |
1) |
Inspect timing chain and gears.
|
|
Material in cylinder
|
1) |
Inspect cylinder for damaged components and/or foreign materials.
|
2) |
Repair or replace as required.
|
|
Seized crankshaft or connecting rod bearings. |
1) |
Inspect crankshaft and connecting rod bearing.
|
|
Bent or broken connecting rod. |
1) |
Inspect connecing rods.
|
|
Broken crankshaft |
|