Subaru Oil Consumption Lawsuit: The Piston-Ring Defect

The Defect

A class-action lawsuit alleged that certain Subaru vehicles with the company’s FB-series engines consumed engine oil at an abnormally high rate because of defective piston rings. Piston rings help seal the combustion chamber; when they do not work correctly, oil can slip past and burn off, so the engine steadily loses oil between changes. Owners said they had to add oil frequently and risked running dangerously low — which can accelerate wear or cause engine damage — and that Subaru knew of the problem but did not adequately disclose it. The affected models were mainly certain 2011–2014 Forester, Legacy, Outback, Impreza and Crosstrek vehicles with the 2.0- or 2.5-liter engines.

Excessive oil consumption is dangerous precisely because a driver may not notice the level dropping until the engine is starved of oil.

The Settlement

Subaru resolved the litigation with a class-action settlement that extended the warranty coverage on the engine for affected owners and reimbursed them for related expenses — such as repairs and oil-consumption testing they had already paid for. The extended warranty was the practical core: it gave owners a defined window in which Subaru would address the problem, including repairs like replacing piston rings or short blocks when a car failed an oil-consumption test.

As with similar auto settlements, keeping documentation of dealer visits and repairs was key to claiming reimbursement.

What Owners Should Know

If you own one of these Subarus, check your oil level regularly between changes — a car that needs frequent topping up may have the problem — and ask a dealer about an oil-consumption test if you suspect it. Keep records of oil purchases, testing and repairs. More generally, monitoring oil level is cheap insurance against a very expensive engine failure on any vehicle.