Subaru WRX: FA20DIT Piston Ringland Failure Under Boost

The FA20DIT 2.0-litre turbocharged direct-injection engine fitted to 2015–2021 WRX models suffers from piston ringland failure — the land between the top and second piston ring cracks or collapses under sustained high-boost or high-RPM load on the stock tune. The failure is accelerated by heat soak, ethanol blends, and any modification that increases boost pressure. Once a ringland cracks, combustion gases blow past the rings into the crankcase, causing catastrophic oil contamination, white or blue smoke, and rapid bearing failure. NHTSA received numerous complaints referencing this failure mode. It is the single most discussed mechanical defect in the VA-chassis WRX community.

• Blue or white smoke from exhaust under hard acceleration or at sustained highway speed
• Rapid oil consumption between service intervals (more than 0.5 L per 1,000 km)
• Rough idle or misfire on one or more cylinders
• Crankcase pressure causing oil cap or dipstick tube to pressurize noticeably at idle
• Loss of power accompanied by a rattling or knocking noise under load

1. 1

   Check for blue or white smoke on hard acceleration and at idle.

2. 2

   Pull the oil dipstick and smell for combustion gases or milky contamination.

3. 3

   Check for excessive crankcase pressure (oil cap blowing off at idle).

4. 4

   Ask for full service history and any evidence of boost or tune modifications.

5. 5

   If a workshop inspection is possible: Compression test all four cylinders; any cylinder below 150 psi or more than 10% variance is a red flag.

$5,500 to $15,000 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 the engine ever been modified, tuned, or run on E85 or any ethanol blend?”
• “Has the car ever been tracked, dynoed, or used in any motorsport activity?”
• “Is there a compression test result on file, and has the engine ever consumed more than half a litre of oil between oil changes?”

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.