Parts for your 2004 Holden Commodore-Exhaust mount

2004 Holden Commodore exhaust mount: what it does and how to look after it

Technical sources such as the Holden VY/VZ Workshop Manual (Exhaust System section) and OEM parts catalogues for 2004 Commodore variants (V6 and V8, sedan, wagon, and ute) list multiple exhaust hanger insulators and brackets along the system. That confirms an exhaust mount is absolutely fitted and relevant on the 2004 Holden Commodore.

On this Commodore, the exhaust mount (often called a hanger or insulator) suspends the exhaust system from the body using rubber isolators and metal brackets. Its job is to keep the pipes, catalytic converter, centre section, and rear muffler aligned while soaking up vibration and allowing the system to move as it heats and cools. Good mounts prevent knocks on the floorpan, stop the tips from sitting wonky in the bumper, and protect welds, flanges, and oxygen sensors from stress. Because the Commodore runs a fairly long exhaust, the mounts do a lot of work over bumps, during hard throttle, and at idle when engine movement is highest.

As part of regular servicing, the mounts deserve a quick once‑over. Rubber can perish, crack, or stretch, especially on cars that see towing, rough roads, or lots of short trips. Telltale signs include a dull knock over speed humps, a rattle at start‑up, droning that’s new, or an exhaust tip that’s shifted in the cut‑out. During an underbody check, look for split rubbers, elongated holes, torn brackets, or rust at the hang points. Replacement is straightforward: safely support the exhaust with a stand, unhook the old rubbers, and slide on new ones. A spritz of silicone spray helps. Sticking with quality OEM‑style rubber is usually best for road cars, firmer polyurethane can add noise and cabin buzz. After fitting, ensure 10–20 mm clearance around the tunnel, crossmembers, heat shields, and the rear bar, then run the engine and recheck for contact. It’s sensible to inspect mounts at every service or roughly every 10,000–15,000 km, and replace them in pairs when wear shows to keep the system sitting true.

• Replace worn or cracked hangers promptly to protect flanges and welds.
• Support the exhaust before removing any mounts, it’s heavier than it looks.
• Check clearances hot and cold to account for thermal expansion.
• Use silicone spray to ease new rubbers on, avoid petroleum grease on rubber.
• Reinspect after a heat cycle, re‑align if any fresh knocks appear.

Popular questions about 2004 Holden Commodore exhaust mounts

How many exhaust mounts does a 2004 Commodore have?
It varies with body style and engine. Most V6 single‑system cars use around three to five hangers from the front pipe to the rear muffler. V8s and models with twin rear sections can have an extra hanger or two to stabilise the additional pipework and muffler mass. The exact count also depends on sedan, wagon, or ute layouts.

When in doubt, a quick visual on a hoist will show each rubber insulator and bracket along the run.

What are the signs the exhaust mounts need replacing?
Common clues include a thud over bumps, a rattle at cold start, a new drone at certain revs, or exhaust tips that sit off‑centre. Underneath, stretched or cracked rubbers, shiny scuff marks on the tunnel or heat shields, and rusty or bent brackets point to tired mounts.

If left too long, the extra movement can stress flanges and O2 sensor wiring, so it’s worth fixing early.

Should owners use rubber or polyurethane hangers?
For most daily‑driven Commodores, quality OEM‑style rubber hangers are the sweet spot—good isolation with factory fit. Polyurethane is firmer and can sharpen location on performance cars, but it may add vibration and cabin noise.

If chasing comfort and OE feel, stick with rubber. If the car runs stiffer mounts elsewhere and a louder system, poly can be considered with the trade‑offs in mind.