GM Service Manual Online
For 1990-2009 cars only

Engine Noise Under Load 6.2L

Cause

Correction

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 ignition controls. Refer to Diagnostic Starting Point - Engine Controls .

Loose torque converter bolts

  1. Inspect the torque converter bolts and flex plate.
  2. Repair, as required.

Cracked flex plate - automatic transmission

  1. Inspect the bolts and flex plate.
  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

Engine Noise Under Load 7.0L

Cause

Correction

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 ignition controls. Refer to Symptoms - Engine Controls .

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