Commodore (VN-VZ) / HSV

1988-2006 / Sedan / Estate / Australia

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

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

Rear Main Seal Leak

Symptoms

Oil drips from the junction of the engine and gearbox. Oil may be visible on the underside of the bellhousing.

Cause

The rear main seal on the 304 is a two-piece rope-type seal (early) or one-piece lip seal (later) that hardens with age. The one-piece seal is far more reliable. Many 304s have been retrofitted with the one-piece seal during rebuilds.

Fix

Replace the rear main seal.

This requires removing the gearbox or engine.

Budget $500-1,000 for the job at a workshop.

If the engine is out for other reasons, the seal itself is $20-40.

Cost mentioned in fix

Budget $500-1,000 for the job$20-40

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

Other known issues

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.

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