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Home >> Pontiac >> 2005 >> Grand Prix GXP >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 2 (Engine Mechanical - 3.8L) >> Diagnostic Information and Procedures >> Engine Noise Under Load

Engine Noise Under Load

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Engine Noise Under Load

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
Detonation or spark knock Verify the correct operation of the Knock Sensor System. Refer to Knock Sensor (KS) System Description in Engine Controls.
Loose torque converter bolts
  • Inspect the torque converter bolts and flywheel.
  • Repair as required.
Cracked flywheel, automatic transmission
  • Inspect the flywheel bolts and flywheel.
  • Repair as required.
Excessive connecting rod bearing clearance Inspect the following components, and repair as required:
  • The connecting rod bearings
  • The connecting rods
  • The crankshaft
Excessive crankshaft bearing clearance Inspect the following components, and repair as required:
  • The crankshaft bearings
  • The crankshaft journals
  • The cylinder block crankshaft bearing bore