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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| •
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Worn crankshaft bearings
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| •
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Loose or out of specification engine flywheel
|
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| •
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Replace the crankshaft and bearings as required.
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| •
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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
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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.
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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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Coolant consumption may or may not cause the engine to
overheat
|
|
| •
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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)
|
| •
|
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.
|
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Worn crankshaft thrust bearing
|
| •
|
Inspect the thrust bearing and crankshaft.
|
| •
|
Repair or replace as required.
|
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Upper engine noise, regardless of engine speed
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Low oil pressure
|
Repair or replace as required.
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Broken valve spring
|
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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Stetched or broken timing chain and/or damaged sprocket teeth
|
Replace the timing chain and sprockets.
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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
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Low oil pressure
|
Repair or required.
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Loose or damaged flywheel
|
Repair or replace the flywheel.
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Damaged oil pan, contacting the oil pump screen
|
| •
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Inspect the oil pump screen.
|
| •
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Repair or replace as required.
|
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Oil pump screen loose, damaged or restricted
|
| •
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Inspect the oil pump screen.
|
| •
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Repair or replace as required.
|
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Excessive piston-to-cylinder bore clearance
|
| •
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Inspect the piston, piston pin and cylinder bore.
|
| •
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Repair or replace as required.
|
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Excessive piston pin-to-piston clearance
|
| •
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Inspect the piston, piston pin and the connecting rod.
|
| •
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Repair or replace as required.
|
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Excessive connecting rod bearing clearance
|
Inspect the following components and repair or replace as required.
| •
|
The connecting rod bearings.
|
| •
|
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
|
| •
|
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
|
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.
|
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Broken crankshaft
|
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Kia Forte: Troubleshooting
Compression Pressure Inspection