Parts for your 2009 Holden Commodore-Oil cap

2009 Holden Commodore oil cap — what it does, where it sits, and how to look after it

Yes, an oil cap is absolutely used on the 2009 Holden Commodore. Technical references including the Holden VE Commodore Owner’s Handbook (MY09), the GM Holden VE Series Service Manual, and ACDelco/GM parts catalogues confirm every 2009 VE Commodore petrol engine (V6 and V8) is fitted with a threaded engine oil filler cap on the rocker/valve cover.

This humble cap pulls more weight than it looks. It seals the top of the engine’s oil fill point to keep dust and moisture out, maintains crankcase sealing so the PCV system can do its job, and prevents oil mist from splashing out under revs. Pop the bonnet and you’ll typically find it on the top of the engine cover or valve cover, marked “Engine Oil” and often showing the recommended viscosity from the handbook.

As part of routine servicing on a 2009 Holden Commodore, the oil cap deserves a quick once-over. Each oil change, wipe the cap clean, check the O-ring or seal for flattening or hardening, and inspect the threads and locking tabs. Refit it hand-tight only—seat it until it contacts the seal, then give it a neat nip, no need to swing off it. Over-tightening can crack the cap or distort the seal, which can weep oil and let in grime.

Replace the oil cap if it shows any of the following:

• Cracks, missing tether, or distorted/brittle seal
• Damaged or cross-threaded neck/cap that won’t tighten squarely
• Persistent oil smell, light misting around the fill point, or a warning about oil level/pressure after recent service checks

A fresh cap is inexpensive insurance. A worn or missing cap can lead to oil loss, messy engine bays, and in some cases rough running from unwanted air entering the crankcase path. For the 2009 VE Commodore’s V6 and V8 engines, the correct cap is a direct-fit part—match by engine code and build year as noted in Holden and ACDelco catalogues, and follow the handbook’s oil spec when topping up.

Tip for Aussie and Kiwi owners: anyone doing long country trips or regular commuting should keep an eye on the cap’s seal condition every 10,000–15,000 kilometres. Clean cap, correct oil, and a proper seal—no dramas, just dependable motoring.

Popular questions about 2009 Holden Commodore oil caps

Where is the oil cap on a 2009 Holden Commodore?
It’s on the top of the engine, threaded into the rocker/valve cover. It’s clearly labelled “Engine Oil”. On V6 and V8 variants the exact position differs slightly under the plastic engine shroud, but it’s always the main fill point up top.

Are V6 and V8 oil caps interchangeable on the 2009 model?
Often they look similar, but it’s best to match the cap to the specific engine. Thread size, sealing height and vent detail can vary. Use the vehicle’s VIN or engine code to select the correct cap as per GM Holden parts data.

Is it safe to drive if the oil cap is missing or broken?
No. Driving without a proper cap can throw oil around the bay, invite dust and moisture into the engine, and upset crankcase ventilation. Replace the cap before driving and check the oil level after refitting.