The Lemon Index
Subaru's 2.5 L turbo flat-4, DOHC in the WRX STI, model years 2015–2021. YouTube likes the 2015 best. Also in the Subaru Impreza (below).
Middle of the pack: YouTube owner tone 50/100, #79 of 165 engines with a YouTube study (in the middle third); no engine-related recall on record, 5 known issues listed below.
Everyday cars with this engine Tap a year for that car's full report.
Model years from EPA version lists. Only years we have a car page for.
Reliability by year
Not enough complaints to chart. Owners filed 9 complaints with the government that we can tie to this engine's cars, 2015–2021, about any part of the car. Performance versions are mostly filed under their base model (a Shelby GT500 is filed as a Mustang), so we only count complaints whose model name or the owner's own words tie them to this engine, and lead with YouTube, recalls and the automaker's repair notes.
Why the car page shows more: the STI page counts 503 complaints and 2 recall campaigns for 2004–2021, everything NHTSA files as "Wrx Sti", other engines included. This page counts only the 9 complaints and 0 recalls we can tie to the Subaru EJ257 2.5 turbo boxer by model name or the owner's own words.
YouTube videos are most positive about the 2015 (53) and least about the 2016 (47); neighboring years share many of the same videos, so small gaps mean little.
How we count: owner complaints only where the car's name and year leave no doubt; YouTube tone from videos that name this engine or its cars. How we count
Owner complaints (NHTSA) are filed by model and year, not engine. We count one for this engine only when the model name and year had no other engine (e.g. "488 GTB", "GT-R"), or when the owner's own words name a version that had only this engine that year (Z06, ZR1, Hellcat, GT500 ...). They cover the whole car (wheels, air bags, electrics ...), not only the engine, and none of them is a failure rate. We chart them only for engines with 30 or more, over 3 or more years. YouTube tone = how positive the videos are, 0–100, from titles and transcripts (praise vs trouble words, the title counts 3 times), weighted by views; a year needs at least 3 videos' worth. A video counts for this engine when its title names the engine or a car that only had this engine in the years it names; a video whose title names no model year counts toward every year of that car, so neighboring years share most of their videos.
All the numbers, year by year
| Year | Cars | Owner complaints | YouTube says | Recalls |
|---|---|---|---|---|
| 2015 | WRX STI | 3 | 53 (133 videos) | 0 |
| 2016 | WRX STI | 3 | 47 (132 videos) | 0 |
| 2017 | WRX STI | 0 | 49 (131 videos) | 0 |
| 2018 | WRX STI | 2 | 48 (134 videos) | 0 |
| 2019 | WRX STI | 1 | 52 (130 videos) | 0 |
| 2020 | WRX STI | 0 | 49 (132 videos) | 0 |
| 2021 | WRX STI | 0 | 50 (134 videos) | 0 |
Recalls on cars with this engine
No NHTSA recalls we can tie to this engine's cars.
Engine problems Subaru told dealers about
Subaru sent dealers 29 repair notes about the engine on these cars, including:
- This Bulletin announces the diagnostic procedures to be followed when diagnosing engine oil leakage on FA and…
- This bulletin announces the availability of reprogramming files to optimize the ECM
- Gear Oil Leaking from Rear Differential Cover
NHTSA manufacturer communications (technical service bulletins), matched by model name and year like the complaints, engine-related ones only. A repair note is not a recall: ask a seller whether it was done.
Known issues on record
- Ringland and piston failure (Parts seller / enthusiast outlet). Detonation can crack a piston ring land, causing low compression, blow-by and oil burning. Parts sellers say it happens on stock cars too, more often with bad tunes, low octane or full throttle at low rpm. Fix: Rebuild with new pistons; Subaru switched to stronger pistons for 2019. 18 owner complaints to NHTSA mention it (GR / GV STI, VA STI).
- Bearing failure from oil starvation (Owner-reported). SlashGear, citing a YouTube mechanic, names oil starvation of the second and third bearings as the main EJ257 problem, which can end in bearing failure. 23 owner complaints to NHTSA mention it (GR / GV STI, VA STI).
- Head gasket leaks (Outlet). Head gasket failures happen on the EJ257 but less often than on other EJ engines, and are more likely with a higher-boost tune, per SlashGear. 1 owner complaint to NHTSA mention it (VA STI).
- Oil consumption (Enthusiast outlet). A cracked ring land lets combustion gas pressurize the crankcase, which burns oil. Rising oil use can be an early warning, so check the level often. 3 owner complaints to NHTSA mention it (GR / GV STI, VA STI).
- Secondary air pump relay recall (Recall). On turbo 2008–2014 Imprezas, including the STI, the relay for the secondary air injection pump can fail and keep the pump running until it overheats, raising fire risk. Fix: Dealer replaces the relay for free (NHTSA 16V-738, Subaru WTM-73). 11 owner complaints to NHTSA mention it (GD STI, GR / GV STI, VA STI).
Sources: MAPerformance: How to avoid Subaru ringland piston failure (Jan 2020), Come and Drive It: Subaru WRX / STI ringland failure, SlashGear: 4 of the worst engines ever made by Subaru (Dec 2025), Subaru of America: Pricing on 2019 WRX STI model (May 2018), NHTSA recall 16V-738: secondary air injection pump relay, turbo Subarus (Oct 2016). The same list as on the STI page.
Every US version with this engine
| Car and versions | Years |
|---|---|
| Subaru WRX STI WRX, WRX STI Type RA | 2015–21 |
Engine code: EJ257. Power: 300–341 hp, factory figures. Versions and years: EPA (fueleconomy.gov). Sources: Subaru EJ engine.
Quick answers
What cars have the Subaru EJ257 2.5 turbo boxer engine?
In the US: the Subaru WRX STI, model years 2015–2021. See the version table for each one.
Is the Subaru EJ257 2.5 turbo boxer reliable?
Mostly, with known issues to check. YouTube owner tone 50/100, #79 of 165 engines with a YouTube study (in the middle third); no engine-related recall on record, 5 known issues listed below. Not enough owner complaints to judge it per car: the government files most performance versions under their base model. Have any used car inspected.
How much horsepower does the Subaru EJ257 2.5 turbo boxer make?
300–341 hp in factory figures, depending on the car.