Parts for your 2020 Holden Colorado-Fuel cap

2020 Holden Colorado fuel cap — what it does, how to look after it, and when to replace

Yes, the 2020 Holden Colorado uses a conventional, screw-on, tethered fuel cap. This isn’t a capless system. The Holden Colorado (RG) Owner’s Manual for MY2020 (Refuelling section) specifies a screw-type, tethered cap that must be tightened until it clicks. GM service information for the RG Colorado likewise calls up an OE-style sealed cap to maintain correct tank behaviour and keep contaminants out. That’s the cap fitted from factory on Australian and New Zealand-delivered 2.8‑litre diesel Colorados.

On this ute, the fuel cap’s job is simple but important: it seals the tank against dust, water and road grime, reduces diesel odour, and helps the tank venting system work as intended. A good seal matters even more if the vehicle tows, works off-road, or spends time on corrugations or the beach.

During regular servicing, it’s worth asking for a quick check of the cap. A technician will look for a perished O‑ring, nicks in the sealing face, a broken tether, or threads that feel rough or loose. If the cap won’t tighten until it clicks, or it feels wobbly on the neck, it’s time for a replacement. Many owners choose to replace the cap proactively at around five years or after heavy off‑road use to avoid nuisance diesel smells or minor leaks.

Day to day, keep things easy:

• Wipe dust or sand off the cap seal and filler neck before refuelling.
• Tighten the cap until it clicks, don’t over-muscle it.
• Avoid resting a dirty cap face-down, use the tether/holder point.
• If you notice diesel weeping around the filler door, check the seal and replace the cap if it’s cracked or flattened.

When replacing, use a genuine Holden/GM cap or a quality aftermarket unit that’s specified for the RG Colorado (2016–2020). That ensures the seal profile, venting characteristics and fit are right for the tank and filler neck. Skipping the cap or running a damaged one can let water and dust into the fuel system—bad news for high‑pressure diesel components—and can also create unpleasant cabin and garage odours.

Does the 2020 Holden Colorado have a capless filler?

No. The 2020 RG Colorado uses a traditional, screw-on, tethered fuel cap. The owner’s manual instructs tightening the cap until it clicks after refuelling, confirming it isn’t a capless design.

How tight should the cap be, and how often should it be replaced?

Tighten until it clicks. There’s no strict replacement interval, have it inspected at each service. Replace it if the O‑ring is cracked or flattened, it won’t click, the tether is broken, or you notice diesel odour or dampness near the filler.

Can it run without a cap for a short trip?

Best not. Driving without a cap can allow dust and water into the tank and can cause diesel smells and spillage. If the cap is lost, fit a correct replacement as soon as possible and avoid off‑road or wet conditions until you do.