Subaru Legacy BM

World's first boxer diesel — technically fascinating, acoustically disappointing. No boxer rumble like the petrol: sounds like a regular diesel with shifting ECU injection noises that vary day to day. Crankshaft failure on 2008-2010 from stress risers in the aluminum block next to steel inserts — Subaru revised the crankshaft three times (12200AA380→AA381→AA480) without ever issuing a recall. DPF clogs on short trips, oil dilution from post-injection during active regen — ECU only estimates dilution, doesn't measure it. 2012+ (XV/Forester SJ) largely free of crank issues. 2015+ (Euro 6) almost trouble-free. Liqui Moly diesel additive lowers regen temperature per community. Timing belt every 100k km mandatory.

• !! Crankshaft Failure on Early Models (2008-2011) from 100,000 km

  Cracks at the rear main bearing journal from insufficient material strength and incorrect factory torque specs. Failure typically between 50-80k miles, often without warning. Subaru corrected both causes (sealant + torque) after 2011.

  Symptoms: Sudden knocking from engine, oil pressure loss, engine seizure
  4,000–10,000 $
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• !! DPF Clogs on Short Trips from 80,000 km

  Diesel particulate filter clogs with predominantly short-trip driving — regeneration doesn't initiate. Check engine light, power loss, forced dealer regeneration.

  Symptoms: Check engine light, power loss, increased consumption, DPF warning light
  800–2,500 $
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• !! Oil Dilution from DPF Regeneration from 60,000 km

  Frequent DPF regeneration injects diesel into the oil — oil level rises, viscosity drops. Accelerated wear if not changed in time.

  Symptoms: Oil level above max, diesel smell on dipstick, thin oil
  200–1,000 $
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+ 2 more engine weaknesses + vehicle weaknesses

Subaru's volume boxer: 2.5L NA in Legacy, Outback, Forester. Oil consumption class action for 2011-2014 models — piston rings didn't seat properly. Cam carrier seal leaks from ~60k miles (labor-intensive). Thermo control valve on 2019-2022 models: plastic housing fails under heat — Subaru extended warranty to 15 years. Improved from 2023.

• !! Oil Consumption — Piston Rings (2011-2014) from 40,000 km

  Class action for 2011-2014 Forester, Legacy, Outback. Piston rings didn't seat due to variable bore roughness. Worst cases: 1 quart per 800 miles.

  Symptoms: Extreme oil consumption, frequent top-ups needed, blue smoke possible
  4,000–6,000 $
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• !! Cam Carrier Seal Leak from 100,000 km

  Known FB engine problem: seal between cam carrier and cylinder head fails. Labor-intensive due to poor access. Service bulletins published.

  Symptoms: Oil stain under engine, oil smell while driving, visible oil seepage at cylinder head
  1,700–6,000 $
  Ad 13270AA29A valve cover gasket right FB2513272AA24A valve cover gasket left FB2510966AA041 spark plug tube sealcam carrier seal Subaru FB25
• !! Thermo Control Valve Failure (2019-2022) from 60,000 km

  Electronic TCV plastic housing fails above 200°F. All warning lights simultaneously (EyeSight, front collision). Warranty extended to 15 years/150k miles. Mechanical thermostat replaces TCV from 2023.

  Symptoms: All warning lights at once, no heater, fault codes P2682/P26A3/P26A5
  1,300–1,800 $
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+ 1 more engine weaknesses + vehicle weaknesses

Six-cylinder boxer: 3.6L naturally aspirated, smooth and torquey. Significantly more reliable than the EJ four-cylinders. Oil leaks at valve covers and timing chain cover at higher mileage are the main concerns. No head gasket issues. 200k+ mile lifespan realistic.

• !! Timing Chain Tensioner Worn from 150,000 km

  Plastic timing chain tensioner wears after 90,000+ miles and can no longer maintain adequate chain tension. Starts with cold-start rattle, can progress to timing chain jump. Expensive repair due to many bolts on the chain cover.

  Symptoms: Rattling on cold start, loud chain noise, misfires at high mileage
  1,500–3,200 $
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• ! Oil Leaks at High Mileage from 120,000 km

  Valve cover gaskets and timing chain cover become leaky at higher mileage. Typical for boxer engines with many sealing surfaces. Not a critical weakness, but noticeable cosmetically and by smell.

  Symptoms: Oil spots under engine, oil smell when engine is hot
  800–2,000 $
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• ! Serpentine Belt Tensioner Worn from 130,000 km

  Belt tensioner spring fatigues after approximately 75,000-95,000 miles. Loss of tension causes slipping, squealing, and in severe cases, failure of the alternator and A/C compressor.

  Symptoms: Squealing from engine bay, A/C failure, battery warning light, overheating
  250–400 $
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Turbo boxer with 2.5L — the WRX engine of the GR/GV era. Same ringland vulnerability as the EJ257 (cast iron pistons with thin ringlands), but slightly less boost from the factory. Oil pickup tube crack, rod bearing failure, and timing belt are the three big concerns. Class action for 2012-2017 models extended warranty to 8 years/100k miles.

• !! Ringland Failure — Piston Breakage from 100,000 km

  Cast iron pistons with thin ringlands crack under detonation (knock). Causes: poor fuel quality, bad tuning, high exhaust gas temperatures. The EJ cliché alongside the head gasket.

  Symptoms: Misfires at idle after high-load driving, increasing oil consumption, blue smoke
  3,500–8,000 $
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• !! Rod Bearing Failure from 120,000 km

  Class action for 2012-2017 WRX/STI: extended warranty to 8 years/100k miles. Oil starvation from boxer sloshing or neglected oil level as primary cause.

  Symptoms: Knocking noise, oil pressure warning, metal particles in oil
  3,500–6,500 $
  Ad 12108AB050 rod bearing set EJ255rod bearing Subaru EJ255crankshaft bearing WRX
• !! Oil Pickup Tube Crack from 130,000 km

  Identical problem to EJ205: brazed joint cracks from vibration. No recall despite known issue since 1996.

  Symptoms: Sudden oil pressure drop, engine noise, oil pressure warning light
  3,000–6,000 $
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+ 2 more engine weaknesses + vehicle weaknesses