Parts for your 2009 Holden Commodore-Manifold gasket

2009 Holden Commodore manifold-gasket — what it does and when to replace it

Yes, a manifold-gasket is absolutely used on the 2009 Holden Commodore. Technical sources including the GM Holden VE Commodore Service Manual (2006–2013), ACDelco parts catalogues, and common workshop texts (Gregory’s/Haynes) specify both intake manifold gaskets and multi‑layer steel (MLS) exhaust manifold gaskets for the VE range. That covers the Alloytec V6 and the 6.0‑litre V8 variants, with moulded rubber/O‑ring style seals on the intake side and MLS gaskets on the exhaust side.

In this Commodore, the manifold-gasket’s job is to keep things sealed where the manifolds bolt to the cylinder heads. On the intake, it prevents unmetered air sneaking in, which would throw off fuel trims, idle quality and performance. On the exhaust, it stops hot gases and noise escaping under the bonnet, protecting nearby components and keeping the oxygen sensor readings honest so the engine runs sweet and efficient.

There’s no fixed replacement interval in the factory schedule, but the gasket condition should be checked any time the manifold comes off, or if symptoms point to a leak. Common tell‑tales include:

• Rough idle, surging, a whistle/hiss, or high long‑term fuel trims (intake leak)
• Tapping/ticking on cold start that quietens warm, soot marks around the flange, or exhaust smell under the bonnet (exhaust leak)

Replacement and maintenance tips for a 2009 Commodore manifold-gasket:

• Use quality parts (OE ACDelco or reputable brands). Intake gaskets on Alloytec often use moulded O‑rings, replace rather than re‑use.
• Follow the service manual torque specs and the centre‑out sequence. A torque wrench is a must to avoid warping or uneven clamp load.
• Clean mating faces gently, avoid gouging the head or manifold. A plastic scraper and solvent works well.
• Don’t slather on sealant. MLS exhaust gaskets go on dry. Only use sensor‑safe RTV where the manual specifically calls for it.
• On V8s, inspect studs and heat shields, replace any stretched or corroded hardware. On V6s, check the plenum O‑rings, PCV hoses and MAP/throttle body seals while you’re there.
• After fitting, clear adaptive trims if applicable and run a quick smoke test or scan fuel trims to confirm the intake side is airtight.

For routine servicing, it’s smart to have the manifold-gasket inspected during major services or whenever you’re in there for spark plugs, rocker cover gaskets, or exhaust work. Catching a small weep or leak early saves drama, petrol, and keeps the Commodore running spot‑on.

Popular questions

Does a 2009 Holden Commodore have intake and exhaust manifold gaskets?
Yes. Both the Alloytec V6 and the 6.0‑litre V8 use intake manifold gaskets and MLS exhaust manifold gaskets, as outlined in the VE Commodore factory service manual and reflected in ACDelco and major gasket catalogues.

What are common signs of a blown manifold-gasket on a VE Commodore?
Intake leaks often cause a hissing noise, rough idle, higher fuel use and lean fuel trims. Exhaust leaks usually present as a ticking on cold start, small soot trails near the flange, and an exhaust smell under the bonnet. Any of these are a cue to test and replace the gasket.

Should both exhaust manifold gaskets be replaced at the same time?
It’s good practice to inspect both banks. If one side has failed, the other may not be far behind due to similar heat cycles. Doing both at once can save labour and ensures a balanced repair, especially on high‑kilometre cars.