Commodore (VN-VZ) / HSV

1988-2006 / Sedan / Estate / Australia

All Commodore (VN-VZ) / HSV problems All workshop issues

Critical Engine, V6 (Alloytec 3.6L, VZ)

Timing Chain and Guide Failure

Symptoms

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.

Cause

The Alloytec V6 uses plastic timing chain guides that become brittle with heat and age. As the guides deteriorate, the chain loses tension, stretches, and can skip teeth. The VZ Alloytec was the first application of this engine in the Commodore, and early units were more susceptible.

Fix

Replace the timing chains (both banks), all guides, and tensioners.

This requires removing the front cover, the engine may need to come forward or partially out of the bay depending on the workshop's preference.

Parts: $300-500.

Labour: 8-14 hours.

Total cost at a workshop: $1,500-3,000.

This is not a DIY job for most people.

Cost mentioned in fix

$300-500$1,500-3,000

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// More Commodore (VN-VZ) / HSV problems

Other known issues

Critical Engine, V6 (Alloytec 3.6L, VZ)

Oil Leaks from Timing Cover

Oil weeping or dripping from the front of the engine, behind the harmonic balancer area.

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.

Common Engine, V8 (Holden 304, VN-VS)

Hydraulic Lifter Noise

Ticking or tapping noise from the top of the engine, worst on cold start. May persist for several minutes or be constant.

Critical Engine, V8 (Holden 304, VN-VS)

Oil Pump Drive Shaft Failure

Sudden loss of oil pressure. Oil pressure warning light illuminates. Engine noise increases rapidly. Catastrophic engine failure if not caught immediately.

View all 20 Commodore (VN-VZ) / HSV problems