Subaru named in class action lawsuit for defect in pistons, engine management system and positive crankcase ventilation in 2009-2014 Impreza WRX vehicles



This is a class action on behalf of owners of 2009-2014 Impreza WRX vehicles (“class vehivcles.” Subaru introduced the class engines in the United States market in late 2007 for the 2008 model year. Class engines are predisposed to premature engine failure. Class vehicles are defective with respect to improperly designed and manufactured pistons and an engine management system and PCV (positive crankcase ventilation) system that subjects class engines engine to premature catastrophic engine piston ringlands failure (the “Piston Ringlands Defect”).

WRX and WRX STi engines are high performance versions of the 2.5 liter displacement EJ series engines used in other model Subaru vehicles including but not limited to the Forrester, Legacy and Outback. These performance modifications nearly doubled the horsepower for WRX and WRX STi engines over the standard base 2.5 liter engine. These performance modifications that created substantially increased power output did not include necessary internal engine modifications to prevent damage to the piston ringlands.

Inadequate class engine piston ringland durability was caused by casting the class engine pistons from hypereutectic aluminum silicon (Al-Si) alloy. While this alloy has some strength attributes over conventional cast aluminum pistons, Al-Si pistons and in particular piston ringland are more brittle. This Al-Si materials selection and cast construction method resulted in insufficient strength pistons in class engines.

Another contributing cause to class engine failure was an inadequate PCV system that allowed excessive engine crankcase oil vapors to be introduced into the engine combustion chambers thereby lowering the overall fuel/air octane mixture. This causes increased combustion forces acting on the piston through a phenomenon know as detonation. Detonation is a well-known cause of internal engine component damage particularly including piston and piston ringland failure.

Failure of class engines due to the Piston Ringland Defect results in sudden power loss and/or stalling that severely compromises the owner’s ability to maintain vehicle control. The defective class engine components and engine management system also causes sudden an catastrophic engine self-destruction as overheated internal parts seize.

The failures in the class engines due to the Piston Ringland Defect pose a serious safety issue while the vehicle is being operated since there is loss of engine power without warning and the loss of power-assisted steering and reduced braking caused by lack of engine vacuum if the engine stalls. In class vehicles equipped with manual transmissions, the drive wheels will lock and cause loss of directional stability and steering if the engine stalls and the clutch is not immediately disengaged.

Katrina H. said
266 days ago
I bought a 2013 WRX hatchback on 7/30/2018 and on 7/30/2018 my WRX experienced complete mechanical engine and turbocharger failure. I have contacted the dealership (McDaniels Subaru of Columbia SC) and Subarus of America both which state there is nothing they can do to help me. I would like to see if I can receive any help in this matter.

David P. said
265 days ago
I have a 2013 STI sedan that spun the bearings at 26,500 miles. Out of pocket was over $5000 to rebuild the engine.

Michael D. said
190 days ago
My 2014 WRX motor threw a rod a month ago. Out of pocket expenses are totaling $8000 to replace it and the warranty from the dealership will not cover it.

Daniel V. said
155 days ago
Spent 7000$ on the engine replacement after Subaru of North America denied helping to pay for anything but 10 hrs of labor. Said because I had an aftermarket blow off valve there was nothing they could do. A blow off valve has nothing to do with a piston ring causing the piston to explode. There is an injustice this company is doing here and we deserve to be compensated for this crap.

Shelia B. said
120 days ago
I have the same issue with my was sti 2013 with 34,000 miles

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