Commodore (VN-VZ) / HSV

1988-2006 / Sedan / Estate / Australia

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

Critical Brakes

Brake Booster Failure (VN-VS)

Symptoms

Hard brake pedal, significantly increased stopping distances. The pedal feels like pushing against a brick wall. May be accompanied by a hissing sound from the engine bay.

Cause

The vacuum brake booster diaphragm perforates with age. A vacuum leak in the booster also causes rough idle because it introduces unmetered air into the intake manifold. On V6 models, the vacuum hose from the intake manifold to the booster can also deteriorate and crack.

Fix

Replace the brake booster.

Check the vacuum hose first, a cracked hose is a $10 fix that mimics booster failure.

A new booster is $200-400.

Reconditioned exchange units are $150-250.

Labour: 2-3 hours.

Cost mentioned in fix

$10$200-400$150-250

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Other known issues

Common Brakes

Rear Caliper Seizure (VT-VZ with IRS)

The car pulls to one side under braking. One rear wheel is noticeably hotter than the other after driving. Rear brake pads wear unevenly. Fuel economy drops. In severe cases, a burning smell from the affected wheel.

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.

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.

All Commodore (VN-VZ) / HSV problems