Cause
| Correction
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Important: A cold piston knock which disappears in 1.5 minutes should be considered acceptable. A cold engine knock usually disappears when the specific cylinder's secondary ignition circuit is grounded out during diagnosis.
A low rumble/knocking may indicate a crankshaft or piston, lower engine, concern.
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Low oil pressure
|
| • | Repair or replace damaged components as required. |
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Worn accessory drive components
Abnormalities such as severe cracking, bumps or missing areas in the accessory drive belt and/or misalignment of system components.
|
| • | Inspect the accessory drive system. |
| • | Repair or replace as required. |
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Loose or damaged crankshaft balancer
|
| • | Inspect the crankshaft balancer. |
| • | Repair or replace as required. |
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Detonation or spark knock
| Verify the correct operation of the ignition controls system. Refer to
Detonation/Spark Knock
in Engine Controls - 6.0L.
|
Loose torque converter bolts
|
| • | Inspect the torque converter bolts and flywheel. |
| • | Repair or replace as required. |
|
Loose or damaged flywheel
| Repair or replace the flywheel.
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Oil pump screen loose, damaged or restricted
|
| • | Inspect the oil pump screen. |
| • | Repair or replace as required. |
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Excessive piston-to-cylinder bore clearance
|
| • | Inspect the piston and cylinder bore. |
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Excessive piston pin-to-bore clearance
|
| • | Inspect the piston, pin, and connecting rod. |
| • | Replace the piston, pin and connecting rod as an assembly, as
required. |
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Excessive connecting rod bearing clearance
| Inspect the following components, and repair as required:
| • | The connecting rod bearings |
| • | The crankshaft journals |
|
Excessive crankshaft bearing clearance
| Inspect the following components, and repair as required:
| • | The crankshaft bearings |
| • | The crankshaft journals |
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Incorrect piston, piston pin and connecting rod installation
Pistons must be installed with the mark or dimple on the top of the piston facing the front of the engine. Piston pins must be centered in the connecting rod pin bore.
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