Subaru Forester: FB25 Piston Ring Oil Consumption

The FB25 2.5-litre direct-injection boxer engine introduced in the SJ Forester (2013-2018) and carried into the SK (2018-present) carries a documented oil consumption defect stemming from insufficient oil control ring tension. The oil control rings on the FB25 are narrower and lower-tension than those on the previous EJ series, intended to reduce friction and improve fuel economy. In practice, a significant proportion of engines consume oil at rates Subaru itself acknowledges as excessive. Subaru issued Technical Service Bulletin 02-157-14R in multiple markets describing a revised piston ring set and updated oil return passages as the remedy. Some engines required short-block replacement under warranty.

• Oil consumption exceeding 1 litre per 1,200 km as measured between oil changes, without any external leak present
• Blue smoke visible from the exhaust on deceleration (engine braking) and at cold startup
• Low oil warning light illuminating before the scheduled service interval is reached
• Oil fouling on the catalytic converter causing a sulphurous smell from the exhaust system under load

1. 1

   Request a documented oil consumption test — Subaru dealers use a protocol measuring consumption over 1,200 km after an oil change to a fixed level.

2. 2

   Check the dipstick and ask the owner to demonstrate the current oil level.

3. 3

   Inspect for blue tinge in exhaust on a cold start and during a firm acceleration run.

4. 4

   Review any warranty correspondence or TSB repair history in the vehicle's service record.

$3,000 to $7,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Has this vehicle had any Subaru TSB work done related to oil consumption, and is there a dealer record?”
• “How often does the oil level need to be checked between services, and has it ever needed topping up?”
• “Has the engine ever triggered a low oil pressure or low oil level warning light?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.