Parts for your 2009 Subaru Forester-Oil cap

2009 Subaru Forester oil cap — purpose, care and when to replace

Yes, the 2009 Subaru Forester absolutely uses an engine oil filler cap. Technical references including the 2009 Forester Owner’s Manual and Subaru’s SH-series Service Manual show and label the oil filler cap under the bonnet, and Subaru’s parts catalogues list a dedicated engine oil filler cap and seal for this model year and its EJ25 engines. So it’s very much a relevant, fitted component on every 2009 Forester, petrol and turbo alike.

The oil cap might look like a simple bit of plastic and rubber, but it does a big job. It seals the top of the engine so oil doesn’t splash out and contaminants don’t get in. A good cap maintains proper crankcase ventilation flow through the PCV system and helps keep the engine bay tidy by preventing oil misting. On the Forester, it’s a twist-on cap you can access easily on the rocker cover under the bonnet, typically marked for engine oil. Hand-tight is the go—no tools needed.

As part of routine servicing, they should crack the cap off, check the O-ring or gasket, and give both the cap and filler neck a quick wipe. If the seal is hard, flattened or cracked, it’s time for a new cap or a new seal. A poor seal can lead to oil smell in the cabin at idle, a messy film around the filler area, or slight rough running from unmetered air entering the crankcase. Genuine or quality aftermarket caps are inexpensive and worth fitting—cheap copies with loose threads or flimsy seals can be more trouble than they’re worth.

How often should it be checked? Every service interval, and any time oil is topped up. Replacing the cap is a 10‑second job: align, twist until snug, and avoid over-tightening so the O-ring isn’t pinched. If the cap ever goes missing, don’t drive far—oil will fling out quickly. Fit a proper replacement before putting on more kilometres.

• Replace the oil cap/seal if: the cap is cracked, the rubber seal is perished, there’s fresh oil mist around the filler neck, or the cap won’t stay tight.

Popular questions

Where is the oil cap on a 2009 Subaru Forester?
It’s on the engine’s rocker cover under the bonnet, clearly marked for engine oil. Look for the twist-off cap near the top of the engine so oil can be added without tools. The exact side varies by engine variant, but it’s easy to spot from above.

What are signs the oil cap needs replacing?
A perished or flattened O-ring, visible cracks, oil residue around the filler neck, or a cap that won’t snug up are all red flags. You might also notice a warm oil smell after a drive or a slightly untidy engine bay from light oil misting.

Can they drive without an oil cap?
Best not. Without a cap, oil can splash out and dust can get in, risking engine damage. If the cap is lost, park up and fit a correct replacement before putting on more kilometres.