Engine Noise Under Load

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Cause	Correction
Low oil pressure	Perform an oil pressure test. Refer to Oil Pressure Diagnosis and Testing . Repair or replace as required.
Detonation or spark knock	Verify the correct operation of the ignition controls. Refer to Detonation/Spark Knock in Engine Controls - 8.1L.
Loose torque converter bolts or improperly installed torque converter, automatic transmission only	Inspect the torque converter bolts and flywheel. Verify correct installation of the torque converter. 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