Forester engines are almost all 2.5L boxer fours, which makes the choice simpler than it looks — but the boxer family changed completely in 2014, and the turbocharged XT models are separate parts throughout. As with every Subaru we list, the head gasket is the thing to understand before you buy, and the generation tells you which failure mode you are dealing with.
Subaru Forester Used Engines — engine options by generation
| Years |
Engine |
Family / VIN code |
Notes |
| 1998–2002 (SF) |
2.5L H4 |
EJ25D then EJ251 |
DOHC early, SOHC from 1999 |
| 2003–2008 (SG) |
2.5L H4 |
EJ251 / EJ253 |
SOHC, the volume engine |
| 2004–2008 (SG) |
2.5L turbo H4 |
EJ255 |
Forester XT — ringland risk |
| 2009–2013 (SH) |
2.5L H4 |
EJ253 |
Final EJ Forester |
| 2009–2013 (SH) |
2.5L turbo H4 |
EJ255 |
XT, 224 hp |
| 2014–2018 (SJ) |
2.5L H4 |
FB25 |
Chain driven — not an EJ substitute |
| 2014–2018 (SJ) |
2.0L turbo H4 |
FA20F |
XT — direct injection, 250 hp |
| 2019–current (SK) |
2.5L H4 |
FB25 DI |
Direct injection, 182 hp |
How to pick the right one
EJ or FB, and 2014 is the line on the Forester. Inside the EJ range the SOHC EJ251 and EJ253 are broadly compatible with the right intake, but the 1998 DOHC EJ25D is a different head design. On XT models, the turbocharged engine is a separate part at every generation — the EJ255 of the earlier XT and the FA20F of the 2014-up XT are not related and neither will fit a naturally aspirated car. Give us the model year and whether the car is an XT and we will match it.
What usually fails on these engines
Head gasket failure is the Forester story as it is across the boxer range, with the SOHC engines usually seeping externally at the bank before failing inwardly. The multi-layer steel gasket introduced late in the EJ run is the one to have. On XT models, ringland failure from detonation under boost is the risk, and it typically shows as a compression loss on cylinder four. The FB25 has largely resolved the gasket issue but consumes oil as the rings wear. Every EJ we list gets a combustion leak test; every turbocharged unit gets bore-scoped.
What ships with every unit
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Compression and leak-down tested before it is listed, with the test sheet in the box.
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VIN matched fitment — send us your VIN and we confirm the engine code against your vehicle before the order ships.
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Written warranty on every engine, with labour coverage available.
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Free freight anywhere in the lower 48, shipped on a pallet to a commercial address or a terminal.
Related reading: Subaru 2.5L Boxer engine guide, all engine guides.
Subaru Forester used engines - frequently asked questions
Which engines did the Subaru Forester use?
Across 1998 to today the Subaru Forester was built with 2.5L H4, 2.5L turbo H4 and 2.0L turbo H4. The table above lists which one belongs to each generation, with the engine family and VIN character that identifies it.
How do I know which engine is in my Subaru Forester?
The eighth character of the VIN encodes the engine on almost every US vehicle, and that is the only reliable way to settle it - two cars of the same year and trim can carry different engines. Send us the VIN and we check the engine code against your vehicle before anything ships.
Will an engine from a different year fit my Subaru Forester?
EJ or FB, and 2014 is the line on the Forester. Inside the EJ range the SOHC EJ251 and EJ253 are broadly compatible with the right intake, but the 1998 DOHC EJ25D is a different head design.
What usually fails on these engines?
Head gasket failure is the Forester story as it is across the boxer range, with the SOHC engines usually seeping externally at the bank before failing inwardly. The multi-layer steel gasket introduced late in the EJ run is the one to have.
What comes with a used Subaru Forester engine?
Every engine is compression and leak-down tested before it is listed and the test sheet ships in the box. Fitment is VIN matched before the order goes out, every engine carries a written warranty with labour coverage available, and freight is free anywhere in the lower 48.
