Subaru Forester
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.
Diesel Forester 147 hp — same risks, less power
Detuned EE20 variant, all problems identical. In Australia even more problematic than Europe due to diesel quality. Buying guide: budget 30-50% below petrol price, pre-purchase with ECU readout.
Engine Weaknesses 5
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
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
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
HPFP failure causes cold start difficulties and misfires. Expensive part due to boxer installation position.
Symptoms: Cold start difficulties, misfires, check engine light
Glow plugs fail, especially on older examples. Poor cold start, increased emissions.
Symptoms: Poor cold start, white smoke on startup, glow plug warning light
Vehicle Weaknesses 3
Recall WQK-47 / NHTSA 14V311: splash water through tank guard gap corrodes brake lines. Brake fluid loss increases stopping distance. Affects 2009–2013 Forester in 21 salt states.
A/C condenser loses refrigerant through stone chips or corrosion — air conditioning stops cooling. Frequently reported problem on Forester SH.
Sway bar end links (drop links) wear out and rattle — known issue on the SH. Inexpensive repair, but if ignored the clunking transfers to the steering feel.
