Parts for your 2020 Holden Commodore-Exhaust gasket

2020 Holden Commodore exhaust gasket — what it does and when to replace it

Short answer: yes, the 2020 Holden Commodore uses exhaust gaskets, so the part is absolutely relevant. This is confirmed by Holden/GM Global Service Information (GSI) for the ZB Commodore (MY18–MY20), the GM Electronic Parts Catalogue (EPC), and ACDelco/Victor Reinz gasket listings for the Opel Insignia B/Commodore platform. These sources show gaskets and seals at key joints, including cylinder head to manifold or turbo, turbo outlet to downpipe (on 2.0T), and various flange or crush-ring seals further down the system.

The exhaust gasket’s job is simple but critical: keep hot exhaust gases sealed inside the system so the engine can breathe properly, the turbo (where fitted) can spool efficiently, and emissions and noise stay within spec. On the 2.0‑litre turbo, there’s a multi‑layer steel gasket at the turbo to cylinder head, plus sealing at the turbo outlet/downpipe. On the 3.6‑litre V6 AWD, you’ll find manifold gaskets and crush‑ring or flat gaskets at flange joints. The diesel variants use sealing rings around the DPF/catalyst joints as well. All of this is exactly what the Holden/GM service manual and parts catalogues lay out for the ZB.

There’s no fixed “time” replacement for exhaust gaskets on a 2020 Commodore, but they should be replaced whenever a joint is disturbed, and any time there are signs of leakage. Most are single‑use by design, especially multi‑layer steel and crush‑ring styles. During servicing, a good workshop will eyeball the joins for soot marks, feel for puffs, and listen for a tick or hiss on cold start. If a section needs to come apart, new OEM‑spec gaskets (and any one‑time nuts or studs) should go back in with the correct torque and tightening sequence per GM GSI.

• Common leak clues: ticking on cold start, a hot/sooty smell, visible black deposits at a flange, poor turbo response (2.0T), or O2/trim faults.
• Fitment tips: clean mating faces, check flanges for warpage, use new fasteners where specified, and avoid lubricants that alter clamp load unless GM explicitly allows it.

Getting the exhaust sealed properly isn’t just about noise—it protects the engine and turbo, keeps fuel trims happy, and helps the Commodore stay road‑legal for emissions in Australia and New Zealand.

Popular questions

Does the 2020 Holden Commodore actually have exhaust gaskets?
Yes. Technical documentation from Holden/GM GSI and the GM EPC shows gaskets and seals at the manifold or turbo interface and along the exhaust’s flanged joints. Parts catalogues from OEM suppliers also list specific gasket sets for the ZB Commodore engines.

Should the exhaust gasket be replaced every time the joint is opened?
Best practice is yes. Most multi‑layer steel and crush‑ring styles are single‑use. When a joint is separated, fit new gaskets and any single‑use fasteners, then tighten to GM torque specs. That prevents repeat leaks and warped flanges.

Can an exhaust leak hurt the engine or turbo?
It can. Upstream leaks can skew oxygen sensor readings, mess with fuel trims, and on the 2.0T reduce turbo efficiency and response. Left alone, leaks can also overheat nearby components and create fumes under the bonnet.