Subaru FB25 Oil Consumption: How Much Is Too Much

You’ve probably heard the line at the counter: “All Subarus burn oil, that’s just what a boxer engine does.” Forget that. A healthy FB25 in a 2014–2018 Forester shouldn’t need you keeping a bottle of oil in the trunk. Problem is, this engine left the factory with an oil-control ring design that lets a real chunk of them drink oil faster than they should — enough to blindside an owner who’s never had to think about it before. Here’s the good part: you can measure it, there’s a written test for it, and the fix runs anywhere from a $30 valve to a full short block.

Which engine, which years

Every non-turbo 2014–2018 Forester sold in Canada runs the same engine: the FB25, a 2.5-litre horizontally opposed four, bolted to either Subaru’s Lineartronic CVT or a six-speed manual. That’s the whole lineup. Got the XT trim? That’s a 2.0-litre turbo, the FA20F — a different engine family, different failure modes entirely. Don’t let a seller tell you it’s the same story.

The risk isn’t spread evenly, either. Subaru revised the oil-control rings partway through this run, and by the 2016 model year the worst of it was behind them. Canadian buying guides call the 2017–2018 2.5i the low-risk years. A 2014–2015 car needs to prove itself — promises don’t count.

The number that decides everything

Here’s the number that actually matters, straight from Subaru’s own oil-consumption service bulletin, and it shows up again in the US class settlement notice: more than one-third of a quart — about 0.3 L — per 1,200 miles (roughly 1,900 km). Go over that consistently and the documented fix is a new short block — pistons, rings, the whole works.

Some perspective, because a number alone doesn’t mean much. The low-oil warning light usually doesn’t trip until you’re down a full litre, and plenty of owners with this problem are topping up every 1,600–2,400 km just to stay ahead of it. Run the math on a 2015 Forester that needs a litre every 5,000 km — that’s roughly three times Subaru’s own limit. Every engine burns a little oil between changes, that’s normal. A dipstick that drops a full litre inside one interval is not, and don’t let anyone tell you otherwise.

What it feels like from the driver’s seat

Nothing dramatic happens at first — that’s what catches people out. Here’s the usual order: dipstick reads a little below full a few weeks after a change; the low-oil light flickers on during a highway run, then quietly goes off like nothing happened; pretty soon you’re the guy with a bottle of 0W-20 riding around in the cargo floor. The worse cases throw in blue-tinged exhaust smoke or an oxygen-sensor/emissions code — oil junking up the sensor’s readings. And because the cylinders lie flat on this engine, oil takes its time draining back down, so the dipstick will lie to you if you check it wrong. Do it cold, on level ground, after the car’s sat all night, stick held straight up against white paper.

Why the FB25 does this, in plain terms

Subaru ran low-tension piston rings on this engine to cut friction and help fuel economy. Good on paper. In practice, on a lot of these engines the oil-control rings and the drain-back holes behind them coke up with carbon. The ring loses its scrape, oil stays sitting on the cylinder wall, and it burns on the next power stroke. Long, steady highway miles make it worse, not better.

The cheap impostor: the PCV valve

Before anybody starts talking about tearing into the engine, replace the PCV valve. That’s the first move, no exceptions. When this little crankcase-ventilation valve — threaded into the valve cover — gums up, crankcase pressure starts pushing oil vapour straight into the intake, and the engine just burns it. On the FB25 it’s a 19 mm socket and a few minutes of labour. If consumption drops noticeably after the swap, you just dodged a four-figure repair. If nothing changes, that’s not money wasted — it tells you and your shop the rings are the real problem, and it’s a data point that helps a goodwill case later.

The official remedy trail — and its Canadian catch

Subaru never called this a recall, and it isn’t one. Check yourself: neither Transport Canada nor NHTSA has a safety recall on the books for FB25 oil consumption — the recall listings for these years show only unrelated stuff like brake-light switches and airbag sensors. Down in the US, the Yaeger v. Subaru class settlement (finalized August 2016) stretched powertrain coverage to 8 years/160,000 km for oil-consumption repairs. But read the fine print before you get excited: it only covers automatic-transmission 2011–2014 Foresters below a specific VIN cutoff — and the part that trips people up — vehicles originally sold in the continental United States. Bought your Forester new in Canada? That settlement does not cover you. Don’t trust a forum thread that says otherwise.

Your actual path in Canada is the dealer’s oil-consumption test, run under Subaru’s TSB (02-1157-14R and the bulletins before it): fresh oil and filter, level set to full and written down, seals put on the dipstick and filler cap, then you come back at around 1,900 km for the reading. Fail it, and the documented remedy is a short block. Two things to watch for: some dealers overfill it at the start to pad the numbers, so check the level yourself before you drive off, and a borderline burner can pass the first interval and then fail the second — push for the extended reading if you’re close. Photograph the dipstick and the odometer every time, with a timestamp on it. Then get on the phone with Subaru Canada, open a case, and ask about goodwill. Persistence and paperwork are what move these along.

What it costs in Canada

Here’s what it actually runs, based on published repair-cost data and what shops around here charge:

• Oil-consumption diagnosis: about $200–$500
• PCV valve replacement: about $150–$400 (do this first, every time)
• Short block / piston-ring service: roughly $4,000–$7,500+ installed at an independent Subaru shop; the dealer will run more
• Full replacement engine (new or remanufactured): $7,000–$12,000+
• A used JDM FB25 long-block plus installation — plenty of Canadian owners go this route — usually lands in the $3,500–$5,500 range. Short parts warranty, no history on it, so test it once it’s in.

What an owner can do this week

Start tracking it yourself. Check the dipstick weekly, cold, on level ground. Log the date, the kilometres, and the level, and only write down amounts you’ve actually measured — no guessing. Stick with the specified 0W-20 full synthetic — our guide to choosing motor oil in Canada covers why viscosity matters on an engine like this — and shorten your oil change interval instead of stretching it out. Fresh oil keeps the rings cleaner, plain and simple. Swap the PCV valve while you’re at it. If your numbers come back excessive, book the dealer test, get the readings in writing, and open a Subaru Canada case at the same time — don’t wait on one before starting the other. This isn’t a one-off, either: same ring-style root cause shows up in the Toyota 2AZ-FE oil-burning problem, just a different remedy trail. And run your VIN through the recall lookup while you’re at it — there are unrelated safety recalls on these years, and those repairs are free; our recalls-in-Canada explainer walks through how that works.

Used-buyer checklist for a 2014–2018 Forester

Show up before the seller fires the car up. Take it cold, on level ground, after it’s sat overnight, and read the dipstick yourself first. Ask one question — “how often do you add oil?” — and watch their face while they answer, not just the words. Then ask for records: a short block already replaced under the TSB or a goodwill claim is actually a point in its favour — get the invoice. Take it on the highway and watch for smoke when you lift off the gas. If the dipstick’s low and the story is “it never needs a drop,” walk away. That engine’s been run low before, and running an engine low kills bearings, full stop. Stick to 2017–2018 where you can, and treat any 2014–2015 as guilty until the consumption numbers say otherwise.

Frequently asked questions

Is it normal for a 2014–2018 Subaru Forester to burn oil? A little, sure — every engine burns some oil. Subaru’s own line for the FB25 is roughly one-third of a quart (about 0.3 L) per 1,900 km. Go past that consistently and you’re out of normal territory, into ring problems. Needing a full litre between changes isn’t normal. Get it tested.

How do I know if my Forester burns too much oil? Low-oil light coming on between changes. A dipstick dropping noticeably within a few thousand kilometres. Blue exhaust smoke. An oxygen-sensor or emissions code. Check the dipstick cold, on level ground, after the car’s sat overnight, and actually track what you add — numbers beat gut feel.

Will Subaru replace my engine for free? Probably not, not in Canada. The 2016 US class settlement covers oil-consumption repairs to 8 years/160,000 km, but only for vehicles originally sold in the continental US — and only early-production 2014 Foresters ahead of a VIN cutoff. Your realistic path up here is the dealer consumption test under Subaru’s TSB, plus a goodwill request to Subaru Canada. Paperwork improves your odds.

Can a PCV valve really cause oil consumption? Yes. A stuck or gummed-up PCV valve lets crankcase pressure push oil vapour into the intake, and the engine just burns it. It’s a cheap part, under an hour of labour — replacing it, and checking the hoses are clear, is the correct first move before anybody talks about engine work. If consumption barely moves afterward, the oil-control rings are the likely culprit.

Should I avoid buying a 2014–2018 Forester because of oil consumption? No, just go in with your eyes open. The risk sits mostly in 2014–2015 — the rings got revised for 2015 and the problem was largely sorted by 2016, so a 2017–2018 2.5i is the low-risk pick. Any candidate still needs a documented consumption test, and a seller who’ll give you a straight answer to “how often do you top up?”

Sources & further reading

• Yaeger v. Subaru oil-consumption settlement — official class notice (court-authorized PDF)
• Gibbs Mura — Subaru oil-consumption class action: covered vehicles and settlement benefits
• Subaru of America dealer letter on the settlement, hosted by NHTSA (PDF)
• Subaru Forester Owners Forum — “FB Series Engine, Oil Burning, Subaru, and You” (TSB test procedure and owner documentation strategy)
• Granger Warranty — Subaru Forester oil-consumption causes and repair cost ranges
• Planet Motors — Subaru Forester years to avoid: a Canadian guide
• Tedious Repairs — Subaru Outback common problems by generation (FB25 ring revision timeline)