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Engine Noise Under Load

WARNING: This page is about a different car, the 2006 Pontiac Montana SV6, 2006 Chevrolet Uplander, and 2006 Buick Terraza. However, it is still accessible from the selected car via links, so may be relevant.
Engine Noise Under Load

Cause Correction
IMPORTANT: The camshaft position actuator may make a slight tapping noise upon cold startup. This is due to the viscosity of the oil that has not yet warmed to proper operating temperatures and should be considered normal for the first 3.5 minutes for cold engine operation.
Low oil pressure
  1. Perform an oil pressure test. Refer to Oil Pressure Diagnosis and Testing .
  2. Repair or replace as required.
Detonation or spark knock Verify the correct operation of the knock sensor system. Refer to Electronic Ignition (EI) System Diagnosis in Engine Controls.
Loose torque converter bolts
  1. Inspect the torque converter bolts and flywheel.
  2. Repair as required.
Cracked flywheel - automatic transmission
  1. Inspect the flywheel bolts and flywheel.
  2. 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
Malfunctioning camshaft position actuator.
Improper viscosity oil, contaminated oil or a plugged or missing camshaft position actuator filter can cause the camshaft position actuator locking pin to malfunction.
  • Verify correct oil viscosity by changing the engine oil and oil filter and reevaluating the concern.
  • Inspect for a missing or plugged camshaft position actuator filter.
  • If filter is missing, replace the filter, replace the camshaft position actuator and change the engine oil and oil filter.
  • If filter is plugged, replace the filter and change the engine oil and oil filter.
  • If no problem is found with the camshaft position actuator filter, replace the camshaft position actuator and change the engine oil and oil filter.
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