Subaru Outback Engine Replacement in Phoenix
Head gasket failure on the EJ25 is why most Outback owners end up reading a page like this one.
The Subaru Outback is one of the most common engine-replacement conversations in Phoenix, and head gasket failure on the naturally aspirated EJ25 is usually the reason. It is a common enough failure mode that it shapes the entire buying decision on these vehicles.
Third-generation Outbacks (2005–2009) used the EJ251 and later EJ253 naturally aspirated boxer engines. Fourth-generation cars (2010–2014) bridged the EJ25 and the FB25, with some model years using either depending on trim. Fifth-generation cars (2015–2019) use the FB25, a direct-injection engine that is not interchangeable with the EJ25.
The head gasket question applies to EJ25-equipped Outbacks specifically. The FB25 has its own issues, but head gasket failure is not one of them. Confirming which engine your Outback has is the first step, and the stamped code on the block is the only thing that settles it on cars near the changeover years.
EJ25 head gaskets are the reason, but the replacement unit may carry them too
The head gasket issue on the naturally aspirated EJ25 is common enough that a used replacement engine has a meaningful chance of carrying the same latent problem. That is the specific risk on this vehicle, and it is avoidable by asking one question: what has been done to the gaskets on the unit you are selling me, and with which parts?
From 2013 onward, the Outback moved to the FB25, a direct-injection engine with a different architecture. The FB25 does not have the same head gasket weakness, but it is not interchangeable with the EJ25. If your Outback is a 2010–2014 model, confirm which engine you have before ordering.
Subaru Outback engines by generation
Three generations, moving from the EJ25 to the FB25, with a transition year in between.
| Generation | Years | Trim | Engine |
|---|---|---|---|
| Third generation (BL / BP) | 2005–2009 | Naturally aspirated | EJ251 / EJ253 |
| Fourth generation (BR / BP) | 2010–2014 | Naturally aspirated (early) | EJ253 |
| Naturally aspirated (late) | FB25 | ||
| Fifth generation (BS) | 2015–2019 | Naturally aspirated | FB25 |
Where Subaru Outback orders go wrong
- EJ25 and FB25 are not interchangeable. Confirm which engine your Outback has, especially on 2010–2014 cars that may be either.
- Head gasket condition on any used EJ25 should be established before purchasing. The replacement unit may carry the same latent problem.
- Turbocharged Outback XT models use the EJ255, a different engine from the naturally aspirated EJ25. Confirm whether your Outback is turbocharged.
None of this needs to be worked out on your own. The Engine Finder asks for the year, model and trim and does the identification from there. The engine code field is optional precisely because most people do not have it.
Check availability for your Subaru Outback
Year, trim and ZIP is enough to start. If you have the VIN it removes the guesswork entirely.
Common questions
Does my Outback have the EJ25 or FB25?
Third-generation Outbacks (2005–2009) have the EJ25. Fifth-generation cars (2015–2019) have the FB25. Fourth-generation cars (2010–2014) can be either depending on model year and trim. The stamped code on the engine block is the definitive answer, especially on cars near the changeover.
Should I replace head gaskets or the whole engine?
It depends on whether the engine overheated and what that did to the cylinder heads. A head gasket job on a boxer engine is labour-intensive, and if the heads need machining the total cost moves toward a used replacement engine. Get the heads assessed first. If you do replace the engine, ask whether head gaskets have been addressed on the replacement unit, because a used EJ25 can carry the same latent problem.
Related pages
- EJ25 EngineSubaru’s 2.5 boxer, head gaskets included.
- FB25 EngineSubaru's 2.5 boxer that replaced the EJ25 in naturally aspirated applications.
- Subaru ForesterEJ25 head gaskets, and whether to repair or replace.
- Subaru LegacyEJ25, EJ255 turbo, FB25 and FA20 across generations, with turbo models the more common replacement candidates.
- Subaru EnginesSubaru boxer engines, head gaskets, and what replacement involves.
- Repair or Replace Your EngineWhether to spend anything at all, before deciding what to spend it on.
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