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Commodore (VN-VZ) / HSV

1988-2006 / Sedan / Estate / Australia

All Commodore (VN-VZ) / HSV problems All workshop issues
Common Engine, V8 (LS1 5.7L / LS2 6.0L, VT-VZ)

Valley Cover Oil Leak

Symptoms

Oil pools in the "valley" between the cylinder banks, visible when the intake manifold is removed. Oil may weep from the manifold area externally.

Cause

The LS1/LS2 has a plastic valley cover (a plate that sits between the cylinder banks, under the intake manifold) with a rubber gasket that deteriorates with heat. The knock sensors sit under this cover, and oil leaking past the gasket can damage the knock sensor wiring harness.

Fix

Replace the valley cover gasket.

This requires removing the intake manifold.

While it's apart, inspect and replace the knock sensor wiring harness if it's oil-soaked or brittle.

Parts: $30-60 for the gasket.

Labour: 2-3 hours.

Cost mentioned in fix
$30-60 for the gasket

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Other known issues

Common Engine, V8 (LS1 5.7L / LS2 6.0L, VT-VZ)

Lifter Tick

Light ticking noise from the top of the engine, usually on cold start. May or may not persist once warm.
Critical Engine, V8 (LS1 5.7L / LS2 6.0L, VT-VZ)

DOD/AFM Lifter Collapse (VZ LS2 with DOD)

Misfiring on specific cylinders, rough idle, check engine light. Metallic knocking from inside the engine.
Common Engine, V6 (Buick/Ecotec 3.8L, VN-VY)

Intake Manifold Gasket Leak

Coolant leak at the junction of the intake manifold and cylinder heads. May present as coolant loss without a visible external leak (coolant enters the intake ports), or as a coolant stain on the side of the engine. Engine may run rough or misfire if coolant enters the combustion chamber.
Critical Engine, V6 (Buick/Ecotec 3.8L, VN-VY)

Harmonic Balancer Failure (Ecotec, VS onwards)

A wobbling pulley on the front of the crankshaft. Knocking or rattling noise from the front of the engine. The drive belt may track poorly or come off.
Common Engine, V6 (Buick/Ecotec 3.8L, VN-VY)

Supercharger Bypass Valve Failure (L67 supercharged V6)

Loss of boost, rattling from the supercharger, reduced performance. The supercharger may make a whining noise that changes with the valve's operation.
Critical Engine, V6 (Alloytec 3.6L, VZ)

Timing Chain and Guide Failure

Rattling noise on cold start that may persist after warm-up. Check engine light with codes related to camshaft timing. Rough idle, misfiring, loss of power. In severe cases, the engine won't start or runs extremely poorly.
View all 20 Commodore (VN-VZ) / HSV problems