Symption
| Suspect area
| Remedy
|
Engine misfire with abnormal internal lower engine noises
|
| • |
Worn crankshaft bearings |
| • |
Loose or out of specification engine flywheel |
|
| • |
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.
|
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
(Check and compare with known good vehicle to determine normal condition.)
| 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 camshaft 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 is not cranked.
Crankshaft does 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 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 connecting rods. |
|
Broken crankshaft
|
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Repair procedures
Special Service Tools