GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Blazer - 2WD 🢒 Engine 🢒 Engine Mechanical - 4.3L 🢒 Lower Engine Noise, Regardless of Engine Speed

Cause

Correction

Low oil pressure
    • Verify oil pressure. Refer to Oil Pressure Diagnosis and Testing .
    • Repair or replace damaged components as required.

Detonation or spark knock
    •  Verify the operation of the ignition controls system. Refer to Diagnostic System Check - Engine Controls in Engine Controls.
    • Repair or replace damaged components as required.

Worn, damaged or improperly installed accessory drive belt - severe cracking, bumps or missing segments in the accessory drive belt
    • Inspect the accessory drive system components.
    • Repair or replace damaged components as required.

Worn, damaged or improperly installed accessory drive system components
    • Inspect the accessory drive system components.
    • Repair or replace damaged components as required.

Worn, damaged or improperly installed crankshaft balancer
    • Inspect the crankshaft balancer.
    • Inspect the crankshaft.
    • Repair or replace damaged components as required.

Worn, damaged or improperly installed engine flywheel
    • Inspect the engine flywheel.
    • Inspect the engine flywheel bolts.
    • Inspect the torque converter.
    • Inspect the torque converter bolts.
    • Inspect the crankshaft.
    • Repair or replace damaged components as required.

Worn, damaged or improperly installed torque converter
    • Inspect the torque converter.
    • Inspect the torque converter bolts.
    • Inspect the engine flywheel.
    • Repair or replace damaged components as required.

Damaged oil pan, contacting the oil pump screen

An oil pan that has been damaged may loosen, improperly position or restrict oil flow at the oil pump screen, preventing proper oil flow to the oil pump.
    • Inspect the oil pan.
    • Inspect the oil pump screen.
    • Repair or replace damaged components as required.

Worn, damaged, improperly installed or restricted oil pump screen

An oil pan that has been damaged may loosen, improperly position or restrict oil flow at the oil pump screen, preventing proper oil flow to the oil pump.
    • Inspect the oil pan.
    • Inspect the oil pump screen.
    • Repair or replace damaged components as required.

Worn, damaged or improperly installed piston

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.
    • Inspect the spark plugs. Refer to Spark Plug Inspection in Engine Controls.
    • Verify engine compression. Refer to Engine Compression Test .
    • Inspect the cylinder bores.
    • Inspect the pistons.
    • Inspect the piston pins.
    • Inspect the connecting rods.
    • Repair or replace damaged components as required.

Worn, damaged or improperly installed connecting rod bearing
    • Inspect the connecting rods.
    • Inspect the connecting rod bearings.
    • Inspect the crankshaft connecting rod journals.
    • Repair or replace damaged components as required.

Worn, damaged or improperly installed crankshaft bearing
    • Inspect the crankshaft bearings.
    • Inspect the crankshaft journals.
    • Repair or replace damaged components as required.