Parts for your 2015 Subaru Forester-Oil cap

2015 Subaru Forester oil cap — what it does and how to look after it

Based on Subaru’s technical literature, the 2015 Subaru Forester absolutely uses an engine oil filler cap. The 2015MY Forester Owner’s Manual (engine compartment overview and Engine Oil sections) and the factory Service Manual for the FB25/FA20F engines both identify and illustrate the oil filler cap under the bonnet. Genuine parts catalogues for these engines also list the oil filler cap and its sealing ring, confirming it’s a fitted and necessary component.

On a 2015 Forester, the oil cap seals the top of the engine’s oil filler neck, keeping clean oil in and dust, moisture, and road grime out. That little cap helps maintain proper crankcase ventilation behaviour, prevents oil misting under the bonnet, and avoids drips that can bake onto hot engine parts and cause a burnt-oil odour. It’s a simple part that does a big job: sealing, protecting, and making top-ups easy.

As part of routine servicing, the oil cap deserves a quick once-over. With the engine cool, remove the cap and check that it turns smoothly, the threads or bayonet lugs aren’t chewed up, and the rubber O-ring isn’t flattened, brittle, or cracked. Wipe the filler neck and cap clean, then refit the cap hand-tight — seat it gently and snug it down without forcing it. If the cap feels loose, doesn’t seat squarely, or you notice fresh oil film around the filler area, it’s time to replace the O-ring or the whole cap.

Symptoms of a dodgy oil cap can include a faint oil smell after driving, light weeping around the filler, or a slightly rough idle from a small air leak into the crankcase. While it’s not common, an air leak here can contribute to drivability issues — so it’s worth addressing early. Use a genuine Subaru cap or a quality equivalent matched to the FB25 (2.5i) or FA20F (2.0XT) engine