Subaru EJ25 Engine Problems: Reliability, Specs & Reviews

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Subaru vehicles and engines are popular all around the world. Their build quality and especially the engines are rock solid.

The EJ25 engine is an example of what you would expect when it works up to its full potential. Not everything is great about the 2.5L engine.

This article will be getting into the detail of the most common Subaru EJ25 engine problems that the owners of this engine faced:

  1. Faulty Turbo System
  2. Issues With The Ringland
  3. Rod Bearing Issues
  4. Oil Cover Gasket Leaks

As you can see, all of these problems are to be deemed level critical, and they will affect your daily driving experience.

This article will focus on the root cause of the issues, what can be done to diagnose them and how they can be fixed.

So, without any further ado, let’s get straight into it!

The 4 Most Common Subaru EJ25 Engine Problems

Should I avoid having the engine of Subaru EJ255? Read my guides to find the truth

As promised, this article will now be solely focused on the issues that were outlined above.

It is recommended to read this section in its entirety, as the information can prove to be quite useful for you in the future.

1. Faulty Turbo System

As many of you may know, the EJ25 engine is turbocharged, which enables it to have that amazing performance that many people know and love.

But this feature of the engine has also caused many problems for users.

The Issue

The Subaru engine is quite old at this point.

With it being more than a decade old, some degree of wear and tear should be expected. If the engine has been driven for more than 150000 miles, you will run into issues.

As the turbo system takes in oil, which passes through many filters, it may get clogged over time.

Their blockage can cause the turbo to not receive the oil in the pressure and quantity required. So, the turbo will not function properly when it doesn’t get the proper flow of oil.


As the engine is dependent on the turbocharger, many symptoms can arise, which can be used to catch the issue as early as possible.

The common indications of a malfunctioning turbo system are:

  • Sudden power loss.
  • Decreased performance.
  • Turbocharger producing a whine.

All of these symptoms can be used to narrow down the issue before figuring out the source.

The decreased performance is something that you will notice, and it is something that should be fixed as early as possible.

Repair Options

Talking about fixing things, there is only one thing you can do to fix the problem: replacing the entire turbo system of the vehicle.

Some of you may be wondering that wouldn’t be enough to clean the filters.

This is an excellent question. The thing is, the turbo system will become faulty if it works in such a state, even for a short period.

The replacement is something that cannot be performed at home. It is a tedious process, which is better left at the hands of professionals.

A new turbocharger will cost you around $1500, and after including the labor costs, you can expect to shell out more than $2000.

2. Issues With The Ringland

The next issue is something that is extremely rare. Many people don’t even know what the Ringland is.

Before you read through this part of the article, you must know that this is mostly experienced by people who mod their engines.

The added performance is something that cannot be handled by the engine’s parts.

The Issue

The Subaru EJ25 engine consists of three piston rings, which make up the Ringland. They are the areas between the piston rings. Many of you may already know where this is heading.

The problem is due to cracks, which are caused by wear and tear. A crack can form, which may or may not increase, depending on how hard the engine is working.

A crack can increase to the point that a part of the Ringland can fall off. If that happens, then you are looking at major engine issues, which may result in you needing to rebuild it.

Identifying The Issue

There are many symptoms associated with the problem of Ringland failure.

These symptoms, when noticed, must be the focus of your attention because you may have to spend thousands of dollars in order to get the engine in working condition.

The symptoms are:

  • Ticking sound coming from the engine.
  • Loss in the compression.
  • Unexpected power loss.
  • Exhaust emitting smoke.

These symptoms are exhibited because the piston will have lost the ability to properly seal off the combustion chamber.

Depending on which Ringland has failed, that respective cylinder will not be able to work properly due to there being a compression loss.

Many of you may be wondering about the reason for the smoke emission from the engine.

Well, the reason for this is, due to there being no seal, some oil may leak out. It can enter the combustion chamber, which may well be burnt and produce smoke as a result.


The damage due to this type of issue is always towards the extreme side.

You may be looking at a whole rebuild of the engine, which includes replacing all of the pistons and the machining of the walls.

If the engine is far too damaged for a rebuild, then you will have to get a new one.

3. Rod Bearing Issues

This next problem in the article is a very serious one. Before we dive into the cause of the issue, let me explain to you the function of the rod bearings in a vehicle.

The bearings have the job of connecting the crankshaft to the connecting rods. They are one of those parts of the Subaru EJ25 engine that are exposed to wear and tear than all others.

Source Of The Problem

So, what could go wrong with the bearings?

Well, most of the issues related to it occur when there is low oil in the engine. These bearings need to be lubricated at all times, so they can function properly.

But that is not everything that can cause issues with the rod bearings. The problem was also reported by people who modified the engine to output more horsepower.

This also suggests that the bearings are only able to handle the stock engine’s load.


Now, the question arises, what would happen if these bearings reached the end of their life?

Well, the first thing that would happen is that the connecting rods would start to knock with the walls of the cylinders.

This is a very serious issue. If anyone’s rod broke, it could cause catastrophic damage to the engine.

You should be on the lookout for these symptoms, which will help identify the issue:

  • The clear sound of rod knock.
  • Oil has metal shavings.
  • There is a drop in the engine’s oil pressure.

All of these symptoms suggest that the bearings need immediate attention. The first symptom, the sound, can get extremely loud and annoying.

There is no way you could possibly miss that. You may also notice that the sound gets louder as the engine is pushed harder.

Fixing The Problem

If you catch the symptoms as soon as possible, the least you would have to do is get the bearings replaced and be good to go.

But if you let the issue be, the worst-case scenario would be that you would have to swap out the motor. This would set you back by thousands of dollars.

4. Oil Cover Gasket Leaks

We have finally arrived at the final problem of this article. I thought it would be good to end this problem list with one that is not that serious.

The leakage of the oil cover gasket is something that can occur on any vehicle. There were many owners of the EJ25 engine that reported the presence of the issue.

The Issue

As the engine is quite old at this point, and most of them may already have been driven for quite some mileage, the gaskets may have sustained some damage due to wear and tear.

It must be noted that the EJ25 has two gaskets. So, the issue could occur on any one of the first.

The leakage issue is something that you can expect after the vehicle has been driven for over 100000 miles.

It is something that must be addressed immediately, or else you will run into many issues.


The leakage of the gaskets can create many symptoms, which can be used to identify the issue as soon as possible.

These indicators are:

  • Smoke coming from the engine bay.
  • Oil spill on the ground where the vehicle is parked.
  • The smell of oil burning.

These symptoms confirm that there is oil leakage in the symptom. If you don’t get the issue looked at and fixed, then you may look at issues such as the failure of the rod bearings.


There is nothing to repair when the gaskets go bad. You have to replace them.

It is recommended to replace both of the gaskets, instead of one, because the other one may be nearing the end of its life too. The replacement process is fairly straightforward.

You may need to remove some parts, but the job is simple enough to be done from the comfort of your own rather than paying the high labor prices.

A brand-new gasket is also quite cheap, so you won’t have to worry about spending hundreds of dollars on getting the problem fixed.

What Is The Subaru EJ25 Engine?

The EJ25 is a 2.5L engine, as is evident by its name. It was unveiled to the world in 1995 and became the strongest EJ engine ever.

It dwarfed all other engines of the same series, such as the EJ15 and even the EJ22.

To be honest, that is to be expected with an engine that has more displacement. The EJ25 had six different variants.

The first one, the EJ25D, was the one that started it all. Then came the OD variant, which was released in 1997. The engine used better pistons and had an increased HP output.

Finally, the third one was the EJ251, which came just one year later, in 1998. This variant was a SOHC one, instead of being DOHC, like the other two, and it had a high compression ratio.

Then came model number 23. It was followed by the numbers 24, 25,and 27, and 29. All of them brought welcome changes and improvement.

Is The EJ25 Engine Reliable?

I must admit that I have seen more reliable engines out there.

Unlike some engines, like the Mazda Rotary 13B, this one falls in the middle of the list. There are some serious issues, which at their worst can cause you to replace the engine.

I have mentioned all of these problems in the article. Users must take extra care of this engine so that they don’t have to worry about the failure of parts such as the rod bearings.

So, if you are ready to keep the engine in pristine condition, then there is a very low chance of you running into any serious issues.

The engine will still be prone to wear and tear, which is something no one can avoid. You can expect some repairs after the 100000-mile mark.

What Cars Use The Subaru EJ25 Engine?

Over the years, the engine has been utilized in many vehicles. It all began with the Impreza, Outback, and the SUS sedan.

The Forester started using it in 1998. Next came the 51 variant, which was used in the Impreza, the Forester, Legacy, and the Outback.

This engine was used from 1999 to 2005, with the Baja being the last one to have it under the hood.

Surprisingly, the 25 updates were reserved for the Subaru Legacy only, from 2000 to 2002. The 53 variant, with an open deck design, was used in the same vehicles like the 51.

The next four variants had a similar division, with the Impreza, the Forester XT, the Baja Turbo, and the Outback XT.

The 59 variant, which many don’t even know exist, was used in the 2004 Legacy, Legacy GT, and the Outback.

Subaru EJ25 Engine Specs

Material of the cylinder block Aluminium only
Material of the cylinder head Aluminium only
Fuel used Petrol driven
Injection type Direct fuel injection
Arrangement Flat-4
No. of cylinders 4
Designof the valvetrain SOHC, DOHC
Bore 99.5mm or 3.91-inches
Stroke 79mm or 3.11-inches
Total displacement 2457cc
Combustion type Turbocharged, Naturally aspirated
Compression 9.5:1, 9.7:1, 10.1:1
Power/HP 155 @ 5600 rpm, 165 @ 5600 rpm, 165 @ 5600 rpm, 173 @ 5600 rpm, 170 @6000 rpm
Torque/ft. lb 140 / 2,800 rpm, 162 / 4,000 rpm, 167 / 4,400 rpm, 166 / 4,000 rpm, 176 / 2,800rpm
Oil weight SAE 5W-30, 5W-40, 0W-30, 10W-30, 10W-40
Oil capacity 4.4quarts w/filter
Firing order 1-3-2-4
Time between oil change 6000-miles (10000 km) or 6-months

The Benefits Of Choosing The Subaru EJ25 Engine

The Subaru EJ25 is a very popular engine. The reason for it being famous is because it performs great. But it does not end there!

There are many other advantages of purchasing the engine, which I will be listed below:

  • The engine has excellent smoothness and balance.
  • The low center of gravity allows it to be more stable and have a more balanced driving experience.
  • The engine has a very smooth idle when compared to an inline engine.
  • The engine also has a growl, which is normally not available in stock cars.
  • As it has a box design, it takes lesser space than a typical engine under the hood.

Frequently Asked Questions

Q1. Is The FA20 More Reliable Than The EJ25?

Yes, it is. The EJ series, in general, has caused many issues for its owners. They complained about there being many different design flaws.

The FA20 has had complaints too, but they were not this serious. The FA20 is a smaller engine, as it is a 2.0L one but is definitely more reliable.

Q2. How Many Miles Will The EJ25 Last?

The engine will last anywhere from 250000 miles to a very impressive 300000 miles. Subaru engines have been known for their durability, and the EJ25 is proof of that.

You will have a memorable driving experience with the engine as long as you don’t run into any issues.

Q3. How Much HP Can An EJ25 Handle?

The 155 HP base engine will be able to handle around 400 HP. That is certainly impressive, and the power boost will be more than double, which is something you will definitely love.

But the engine may run into issues with the performance upgrade, like with the rod bearings.


Although there are many Subaru ej25 engine problems, I can assure you that the engine will give you a very good time. What you must keep in mind is that it is quite old at this point.

This means that the one you get will already be used a lot. So, you must be prepared to spend some money to get the engine back in working condition.

This will ensure that you don’t run into many issues in the future.

Other than that, my advice is that you should get any and all problems fixed as soon as possible and keep the engine maintained at all times.

That is the key to its longevity, so you can reach that sweet 300000-mile mark!