Parts for your 2009 Subaru Forester-Fuel cap

2009 Subaru Forester fuel cap — purpose, care, and replacement

Based on the 2009 Subaru Forester Owner’s Manual (Fuel filler lid and cap), the Subaru Factory Service Manual for the Forester SH (Evaporative Emission Control System), and the Subaru Genuine Parts Catalogue for this model, the 2009 Forester is fitted with a threaded, tethered fuel cap. It’s a key part of the vehicle’s sealed EVAP system and is absolutely relevant to how the car manages petrol vapour and emissions.

On a 2009 Subaru Forester, the fuel cap does more than keep dust and rain out. It seals the tank so the EVAP system can capture and route petrol vapour back to the engine, reducing emissions and fuel smell around the car. A good cap helps maintain proper tank pressure and vacuum, which in turn keeps the Check Engine light at bay and prevents EVAP leak fault codes. Subaru specifies tightening the cap until it clicks to ensure the seal is properly seated.

As part of servicing, it’s worth giving the fuel cap some attention. The rubber sealing ring hardens with age, and gravel roads or coastal air can speed that up. If the cap is cracked, the gasket is flattened, or there’s a persistent petrol odour, fit a quality replacement—ideally genuine or an equivalent that’s EVAP-compliant for Subaru models. Petrol Foresters use an unleaded cap, if the vehicle is a rare diesel variant, make sure the cap is clearly marked for diesel use. Avoid generic caps that don’t specify Forester SH compatibility.

• Signs a cap’s on the way out: recurring Check Engine light after refuelling, faint fuel smell, visible cracks, or a cap that won’t “click.”
• Quick care at service time: wipe the filler neck and cap seal with a clean, dry cloth, check the tether and ratchet, ensure it tightens until it clicks several times. Don’t lubricate with petroleum-based products—if needed, a tiny amount of silicone-safe rubber conditioner is fine.
• Replacement timing: many owners swap the cap proactively every 5–7 years, sooner if doing lots of dusty kilometres.

If the light stays on after refuelling, re-seat the cap and drive normally for a couple of trips. Still lit? It may have logged an EVAP small leak—often traced to a tired cap—so testing or a fresh cap can save time and hassle.

Popular questions

What fuel cap fits a 2009 Subaru Forester?
It takes a threaded, EVAP-rated cap designed for the Subaru Forester SH series. A genuine Subaru cap or a reputable equivalent specified for the 2009 Forester will ensure the correct seal and the right “click” torque. If yours is a diesel variant, use a diesel-labelled cap.

Why did the Check Engine light come on after refuelling?
Most commonly, the cap wasn’t tightened until it clicked, or the seal is worn. Refit and tighten the cap and drive for a couple of trips, the light often clears. If not, the cap may be leaking and due for replacement.

How often should the fuel cap be replaced?
There’s no strict interval, but many replace it every 5–7 years, or sooner if there’s a fuel smell, visible wear, or repeat EVAP leak codes. It’s a cheap, quick fix that can prevent nuisance warnings.