Cause
| Correction
|
|
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.
|
Low oil pressure
|
| • | Perform an oil pressure test. Refer to Oil Pressure Diagnosis
and Testing. |
| • | Repair or replace damaged components as required. |
|
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. |
|
Loose or damaged crankshaft balancer
|
| • | Inspect the crankshaft balancer. |
| • | Repair or replace as required. |
|
Detonation or spark knock
| Verify the correct operation of the ignition
controls system. Refer to the Engine Controls section.
|
Loose
torque converter bolts (automatic transmission only)
|
| • | Inspect the torque converter bolts and flywheel. |
| • | Repair or replace as required. |
|
Loose or damaged flywheel
| Repair or replace the flywheel.
|
Damaged oil pan, contacting the oil pump screen
(An oil pan that has been damaged may improperly position the oil pump
screen, preventing proper oil flow to the oil pump.)
|
| • | 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 and cylinder bore. |
|
Excessive piston pin-to-bore 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 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 |
|
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.)
|
| • | Verify the pistons, piston pins and connecting rods are installed
correctly. |
|
