2015–2021 Subaru WRX: Engine knock or rod bearing failure (2.0L turbo FA20DIT)
Likely causes, ranked
- Rod bearing failure, often cylinder 3 (short block replacement)Shop
- Low oil level or oil starvationDIY
- High load at low rpm (lugging) or aggressive tunesDIY
Real-owner fix counts will appear here as reports come in.
DIY or shop: See DIY or shop section
Parts to check
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Symptom: A knock that rises with rpm, low oil pressure, metal in the oil, and in the worst case the engine seizes.
Likely causes
- Rod bearing wear. A shop on Diagnostic Network reports several FA20 turbo failures starting at the No. 3 rod bearing, including stock engines with regular oil changes.
- Oil level and starvation. Owners stress keeping the oil full and changing it often.
- How the car is driven or tuned. r/WRX owners report more failures on tuned cars and warn against full throttle at low rpm in high gears.
DIY or shop?
Shop. Owners mention installing a new short block through a specialist as an alternative to a dealer replacement.
Useful steps
- Stop driving at the first knock and have it towed.
- Check the oil level every fill-up.
- Avoid lugging the engine. Downshift before accelerating hard.
Vehicle focus: 2015–2021 Subaru WRX.
Safety / mechanic note
A rod bearing failure can make the engine seize at speed. Verify with a mechanic immediately.
Recalls & service bulletins
No recalls or service bulletins are listed for this page yet.
NHTSA complaints: 25 keyword-matched complaints (of 241 unique complaints filed under NHTSA model names WRX, 2015–2021; NHTSA complaints API by model year, queried 2026-10-15).
Always check your VIN for open recalls at nhtsa.gov/recalls.
Sources
What actually fixed it?
Had this problem? Tell other owners what the real fix was. Reports are counted above; we never show made-up numbers.