Parts for your 2017 Subaru Impreza-Oil seals

2017 Subaru Impreza oil seals — what they do and when to sort them

Oil seals are absolutely used on the 2017 Subaru Impreza. Subaru’s factory service information for the 2017MY Impreza (FB20 engine and TR580 Lineartronic CVT) and the Subaru Electronic Parts Catalogue specify multiple oil seals, including front and rear crankshaft oil seals, front differential/axle (CVT) side oil seals, and rear differential oil seals. That makes oil-seals a relevant service item on this model.

On this Impreza, oil seals keep engine, transmission and diff fluids where they belong, while keeping dust and water out. They sit around rotating shafts and in key housings, using a spring-loaded lip and the right rubber compound to hold pressure and temperature without weeping. When they harden with age or groove their mating surface, leaks start, leading to mess, burnt-oil smells, slipping belts, or in bad cases, contamination of the clutch or CVT.

As part of regular servicing, oil seals aren’t replaced on a fixed interval, they’re inspected and changed on condition. It’s smart, though, to replace certain seals “while you’re there” to save labour later.

• Engine: front and rear crankshaft oil seals, rocker/valve cover gaskets and spark plug tube seals (for top-end oil control).
• Transmission/Driveline: CVT/front diff side (axle) oil seals, rear differential side seals and pinion seal.

Signs it’s time to act include a mist of oil around the crank pulley and lower timing cover, oil tracking at the bellhousing joint, dampness where the CVT axles enter the case, or drips on the undertray. A hot, oily whiff after a drive is another giveaway.

Best practice when replacing: use quality seals (genuine or reputable aftermarket), lightly lubricate the seal lip, inspect the shaft for grooves, and press the seal square and to the specified depth. Refresh related O-rings and RTV where the manual calls for it. Check crankcase ventilation (PCV) so pressure doesn’t push new seals out. On the FB20, timing is chain-driven, many techs combine a front crank seal with timing cover work if it’s already open. The rear main is typically done when the gearbox is out (manual clutch work or CVT removal). CVT/front diff side seals are done if there’s seepage at the axle stubs.

For Aussie and Kiwi conditions—heat, dust, and long kilometres—ask for a quick leak check at each service and before long trips. Fix small weeps early to avoid oil on belts or exhausts.

• Popular questions about 2017 Subaru Impreza oil seals

Do FB20 engines have separate camshaft oil seals?
The FB20 in the 2017 Impreza doesn’t use the classic external round camshaft oil seals found on older EJ engines. The cam carriers and covers are sealed with form-in-place sealant and gaskets as specified in Subaru service procedures. That means there’s no routine “cam seal” replacement, but any reseal work should follow the factory sealant specs and patterns.

How long do oil seals last and what does replacement involve?
There’s no fixed lifespan, many go well past 150,000 km. Replacement is driven by leaks or when access is convenient. A front crank seal is usually a straightforward job for a trained tech. A rear main needs gearbox removal, so it’s commonly done during clutch work (manual) or if the CVT is already out. CVT/front diff axle seals are mid-level jobs done when seepage starts.

Is it OK to monitor a small seep, or should it be fixed straight away?
A light mist can be monitored if engine oil level is checked regularly and the leak isn’t reaching belts, the exhaust, or the clutch/CVT. If oil is hitting hot parts, worsening quickly, or dripping onto the driveway, book it in sooner rather than later to avoid secondary damage.