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