Subaru is famous for producing highly reliable vehicles – but of course, even the most reliable engine can only last so long. This was certainly the case with the Subaru 2.5 engine, which was noteworthy for its vulnerability to gasket problems. That leaves the question: what can you expect in terms of Subaru 2.5 engine life expectancy?
Many factors are involved, but the simple answer is that you can expect a 2.5 engine to have a life expectancy of about 300,000 miles. However, there are a handful of things which can affect the lifespan of any given engine, and I’ve compiled a list of them below.
What is the life expectancy of a Subaru 2.5 engine?
Generally speaking, a Subaru 2.5 engine has the ability to run between 250,000 and 300,000 miles before needing any kind of significant auto maintenance or repair. Since most drivers average around 14,000 miles per year, this would mean that a Subaru 2.5 engine could conceivably run for over two decades.
- It’s crucial to keep in mind that this life expectancy hinges on you practicing proper maintenance on your vehicle. You’ll need to be very diligent in taking care of the engine, which means changing your oil exactly when you’re supposed to.
- It also means getting your coolant flushed every few years, as coolant becomes contaminated over time and can damage an engine if not changed out.
- An additional step to preserve your engine is to clean the battery regularly. Car batteries can develop a gunky, crusty buildup over time, which can damage the engine if it isn’t clean – so check your battery every so often and make sure it’s clear of buildup.
Of course, unexpected issues can always pop up in automotive engines. To make sure that your engine can last as long as possible, be sure to be attentive to any check engine lights or irregular performance, and take your car to an auto repair shop if it needs maintenance.
Is the Subaru 2.5 a good engine?
Based on my experience, people are hesitant to purchase a Subaru with the 2.5 engine, given it’s troubled history. This attitude isn’t entirely unwarranted IMHO, but it’s valuable to fully understand the situation with the Subaru 2.5 engine.
- After its initial release, the Subaru 2.5 L became somewhat infamous for maintenance problems, which has led some people to assume that the 2.5 engine is fundamentally flawed. But the truth is a bit more complicated.
- The original problematic Subaru 2.5 engine was the EJ25 2.5-liter boxer. It tended to have serious problems due to its design and the unreliable material of its gaskets, which could mean permanent and practically irreparable damage (I’ll explain why in a moment).
- However, from 2009 to 2012, Subaru worked on developing a solution to these problems, designing a new 2.5-liter engine to eliminate the gasket issue – which means that after 2012, the Subaru 2.5 L engine life expectancy became dramatically longer on average.
- As a result, Subarus with 2.5 engines, like the Forester or Outback, enjoy the same high degree of performance and quality as any other Subaru.
With that being said, be sure to check the age of the vehicle, mileage, and engine condition when purchasing a Subaru with a 2.5 L engine. To avoid the problems of the original engine model, stick to cars from 2012 onward.
Common Subaru 2.5 engine problems
For the most part, the Subaru 2.5 engine had a lot fewer problems than other engines from other manufactures (IMHO).
The Boxer engine is a flawed design (my opinion)
The root of Subaru’s problem is the use of boxer engines (also known as a “flat” engine). This engine type is quite different from the common transverse engines you will see in most modern cars.
Most car companies typically use engines in which the pistons are arranged vertically, whether in a “v” shape or vertical rows; this means that when the car is at rest, fluids like coolant and oil drain down and out of the car.
But Subaru is unique among major manufacturers in that it uses boxer engines, which are flat engines whose pistons are arranged horizontally. The major advantage of boxer engines is that they’re safer in the event of a collision: since the boxer engine is lower in height, a head-on collision will push an engine through the car’s floor, not into the driver’s seat.
Gasket failure is the main thing to watch out for
Since the engine is arranged on a horizontal plane when the car is at rest, coolant and oil have nowhere to drain and will simply pool on the gaskets. For those of you who don’t know, gaskets are the cushioning and sealing materials that join irregular surfaces within the car engine.
Properly functioning gaskets are important for avoiding liquid and gas leaks in the engine.
- Because older boxer engines can put such strain on gaskets, they can quickly be worn down – especially when they’re made of an unreliable material, as the early EJ25 2.5-liter engines were – leading to oil leaking out of the engine and damaging the car.
- And because gasket replacement is difficult and expensive, this meant that leakage could be either a fatal problem or a costly fix. To add insult to injury, these damages could often shave hundreds of thousands of miles off a Subaru’s lifespan.
- Whereas an extremely well-maintained Subaru 2.5 L engine has a life expectancy of 300,000 miles, these older Subarus would begin to see considerable damage when they had been driven as few as 90,000 or 150,000 miles.
- Keep in mind that coolant leaks can lead to fire. Take this very seriously!
However, as I mentioned, Subaru has implemented many changes, including improving the engine’s material and overhauling its design, to combat these problems. This has resulted in far fewer issues with newer 2.5 engines.
With that being said, if you’re driving or plan on buying a Subaru from before 2009, determine whether it has a 2.5L engine and what kind of state it’s in, as these problems still do tend to exist in older cars – especially those that have already seen a good deal of wear and tear.
The best way to do this is to check the oil with a dipstick. When you do this, see whether the oil has a milky white quality, as this can be a very strong indicator that the light-colored coolant is mixing with the dark-colored motor oil.
On the other hand, it won’t necessarily be a death sentence for your Subaru – after all, if the car’s engine has made it to 2021, that means that it was probably kept in decent enough condition that it will be safe and drivable.
How many miles will a Subaru 2.5 engine last?
Ultimately, the lifespan of a Subaru 2.5 L engine can vary considerably depending on how it’s maintained. If you don’t take care of it, especially when it’s in an older model, you won’t get a ton of mileage (pun intended) out of the engine – in some cases, as few as 90,000 miles.
But if you’re proactive when it comes to taking care of your engine (like checking the oil, replacing the coolant, and cleaning the battery), you’ll be in a much better position to mitigate any problems.
You may be able to drive a Subaru 2.5-liter engine for upwards of 250,000 miles – even 300,000. In other words: just doing regular maintenance can help you keep the same car for nearly 20 years.
