Detonation cracks the second piston ringland, destroying the engine — common in tuned 2008-2014 WRX/STI.
Reviewed by SubaruReview Editorial Team · Last reviewed 2026-05-10 · Editorial standards
How this problem ranks against the other documented WRX / STI failures — cost, severity, and DIY difficulty at a glance.
| Problem | Years | Severity | Repair cost | DIY |
|---|---|---|---|---|
| EJ255/EJ257 Ringland Failure (this page) | 2008-2014 | Critical | $4,500–$8,500 | 5/5 |
| EJ257 Rod Bearing Failure & STI Rod Knock (2004-2021) | 2004-2021 | Critical | $400–$12,000 | 5/5 |
| 2022+ WRX FA24 RTV Oil Pickup Clog | 2022-2024 | Critical | $2,200–$4,000 | 4/5 |
| Boost Leak from Y-Pipe | 2002-2014 | Major | $150–$350 | 3/5 |
| Subaru WRX Turbo Banjo Bolt Screen Oil Starvation | 2002-2014 | Critical | $400–$2,500 | 4/5 |
| WRX FA20 Bent Connecting Rod | 2015-2021 | Critical | $6,500–$11,000 | 5/5 |
This is one of several documented WRX / STI problems we track, and it fits inside the broader Engine Guides guide. If you're weighing repair against replacement, cross-check the Subaru repair-cost database and any open NHTSA recalls on your VIN before booking a shop.
Knock under boost cracks the ring land between the second and third compression rings on cylinder #4 (the lean cylinder). Compression drops, oil burns, and the engine usually needs a short-block replacement.
Lean fueling on cylinder #4 caused by stock fuel-rail design, combined with marginal knock control and low-octane fuel. Aftermarket tunes that lean out AFR accelerate the failure.
Lean fueling on cylinder #4 caused by stock fuel-rail design, combined with marginal knock control and low-octane fuel. Aftermarket tunes that lean out AFR accelerate the failure.
National average $4,500–$8,500. Short-block + labor; closed-deck builds run $9-15k
Difficulty 5/5. Replace short-block with built motor (forged pistons, ARP studs)
Sudden loss of power under boost; Smoke from exhaust, especially on overrun; Compression test shows #4 cylinder 30-40% lower than the others; Misfire codes P0304 / P0301; Oil consumption spikes overnight
Owners typically pay $4,500–$8,500 at an independent Subaru shop, parts and labor included. Our Subaru Head Gasket Replacement Cost guide breaks the job down by parts, labor hours, and where the money actually goes.
The same generation also sees EJ257 Rod Bearing Failure & STI Rod Knock (2004-2021) and 2022+ WRX FA24 RTV Oil Pickup Clog. Both are documented with symptoms, cost, and a permanent-fix walkthrough — see the full list in the WRX / STI hub.
Cross-check NHTSA campaign 18V-846, which covers FA20 Valve Spring Fracture on 2012-2014 BRZ/Forester XT/WRX/Legacy. Recall work is free at any Subaru dealer — always run your VIN before paying for the fix.
We rate it 5/5 on our DIY scale. Most owners come out ahead with an independent Subaru shop; read labor-hour benchmarks in the repair-costs hub before you commit tools and a weekend.
It's part of our Engine Guides cluster, which collects every article covering the same system as this failure.
Same EJ-family boxer — the failure mode carries across every chassis this engine shipped in.
Same failure mechanism documented on a different Subaru — shares components with this article.
EJ, FA, FB, and EZ boxer deep-dives — the engine background this failure sits inside.
Dig into the Problems Database to plan your next maintenance sprint, or browse every model hub for buyer's guides, generation breakdowns, and known-issue lists.