Parts for your 2015 Subaru Forester-Oil seals

2015 Subaru Forester oil-seals — what they do and when to replace them

Oil-seals absolutely are used on the 2015 Subaru Forester. Subaru’s 2015 Forester Service Manual (via Subaru Technical Information System) and the genuine parts catalog list multiple seals across the vehicle: front and rear crankshaft seals on the FB-series engine, torque converter/front pump and driveshaft/differential side seals in the Lineartronic CVT, and pinion/side seals in the front and rear differentials. While certain areas on the FB engine use form-in-place gasket (sealant) — for example, cam carriers and timing cover — rotating shafts rely on conventional oil-seals to keep fluids where they belong.

In day-to-day terms, oil-seals keep engine, transmission and diff lubricants inside the housings while keeping dust and water out. They’re typically made from high-temp elastomers with a spring-loaded lip that rides on a machined surface. When they harden, get nicked, or the shaft surface wears, leaks can start — leaving spots under the car, a whiff of burning oil near the exhaust, or a greasy buildup around the bellhousing or diff.

• Engine: front crankshaft seal, rear main seal.
• Transmission (CVT/Manual): torque converter or input/pump seal, front differential/driveshaft side seals.
• AWD system: front and rear differential pinion and side seals.

For servicing in Australia or New Zealand, there’s no set kilometre interval to replace oil-seals, they’re done on condition. A good workshop will check for seepage at every regular service (around 10–15,000 km), clean down suspect areas, and recheck. Small seeps can be monitored, active leaks should be sorted promptly to protect clutches, the CVT, and rubber mounts.

When replacement’s needed, it pays to use quality (often FKM/Viton) seals and the correct installer tools. The crank pulley or transmission may need to come out for access, so many owners bundle rear main or torque converter/pump seal work with clutch jobs (manual) or major CVT service. After any seal replacement, fluid levels should be set precisely to spec, and the PCV system and breathers checked — excess crankcase pressure can force new seals to weep.

• Best practice: confirm the leak source with UV dye, inspect the shaft surface for grooves, set seal depth and orientation exactly, lightly oil the lip at install, and verify breathers/PCV are clear.

Done right, fresh oil-seals help the Forester stay clean, reliable and leak-free for many more kilometres.

Popular questions

Does the 2015 Forester actually use oil-seals, or is everything sealed with RTV?
Yes, it uses both. The FB engine uses sealant for components like the timing cover and cam carriers, but it still relies on conventional oil-seals at the front and rear of the crankshaft. The transmission and differentials also use multiple shaft and side seals.

When should oil-seals be replaced on a 2015 Forester?
They’re replaced when leaking or when access is convenient during related work. Typical signs are fresh oil or trans fluid around the bellhousing, sump area, or diff flanges, spots on the driveway, or an oil smell after a drive. A technician will inspect at each service and advise.

What causes repeated oil-seal leaks on these cars?
Common culprits include hardened seals from heat and age, worn shaft surfaces, crankcase pressure from a blocked PCV, overfilled fluids, and poor installation. Checking the PCV/breathers and using quality seals with proper tools goes a long way to preventing repeat issues.