Which Subaru Engines To Avoid? The Detailed Anwer

Are you considering buying a Subaru and checking which Subaru engines to avoid?

You have found the right article!

Subaru is a renowned company that makes automotive engines. Over the past years, Subaru engines have had many problems.

Only some of these engines comply with the quality standards. Naturally, you do not want to lose money because of your new car.

Subaru Engines Should To Avoid

Subaru Engines to Avoid

Here are two Subaru engines you should avoid.

Subaru 2.5-L Turbo 4 Cylinder

The Subaru repair team is reliable, but it is challenging to stay committed to a product that can injure itself and requires an engine change that costs between $8,000 and $12,000. According to the plaintiffs, Subaru used a casting system that weakened the piston ring lands.

The PCV system caused crankcase oil vapor to enter the explosive chamber. This condition reduces the fuel/octane mixture and places a heavy load on the pistons, breaking and damaging the engine.

The Impreza WRX and WRX STI drivers said their vehicles suddenly lose power and stop or fail the engine because its internal parts get too hot and sticky. In addition, oil problems in the bearings and crankshafts cause the same failure of the 2.5-L engine.

Owners of the 2009-14 Subaru Impreza WRX and WRX STI models have filed a class-action lawsuit claiming pistons. PCV (positive crankcase ventilation) systems in 2. 5-L efficient charging engines could be hot or inefficient, which requires hefty technical repair.

Also Read: Ford Edge Years to Avoid (Avoid these models)

Subaru EJ25

The Subaru EJ25 was one of their vehicles’ most commonly used Subaru engines and came in two forms. It was a 2.5-liter boxing engine with a double camshaft. However, from its inception, EJ 25 was plagued with problems.

These problems include oil burn, oil shortage, and head gasket problems. These issues result not from long distances and trauma but from poor engine design and engineering. In addition, it had many quality concerns.

Now let us talk about these Subaru engine problems one by one.

3 Subaru Engine Problems

Subaru Engine Problems

Almost all EJ 25 engines face head gasket problems. This problem is more common in early models. Also, the Subaru used low-quality head gasket components.

1: Oil Leakage from the Engine

One of the most common engine problems Subaru owners have experienced is faulty head gaskets. Challenges passed through a few models for five years. The first group is the first EJ25D 2.5-liter boxer engine found mainly in Legacy, Legacy Outback, Forester, and Impreza from 1996 to 1999.

The second group of head gasket problems came with the EJ251, EJ252, and EJ253 2.5 liter box engines.

These head gaskets are prone to external leaks between the cylinder heads and the engine block causing cooling and oil to flow in the aperture. In both cases, the problem depends on the type of head gasket used, not the engine itself. In all the problem vehicles, the head gasket used was a single graphite-coated head gasket known to lose its adhesion at about the 100,000-mile mark.

Undressing and peeling off this adhesive resulted in the gasket cap of the head becoming vulnerable. Subaru fixed the issue by extending its powertrain warranty and now uses an uncovered multilayer head gasket.

2: Oil and Coolant in the Chamber

Oil or a cooling substance can penetrate the burning chamber and begin to burn. When the oil burns, you can see the black smoke coming out of the exhaust.

If a coolant burns during a fire, white smoke will come out of the car exhaust. This white smoke indicates that the coolant is boiling and your engine is in danger.

3: Excessive Oil Use

Users have consistently reported excessive oil use in their Subarus. Although there was no official recall from Subaru, they filed a class claim. The lawsuit settled out of court because owners claimed that the 2011 to 2015 models Subaru Forester, Outback, Crosstrek, Impreza, and Legacy used high oil prices among common uses.

Boxer Engine of the Subaru

Boxer Engine of the Subaru

The EN engine series, utilized in Subaru Kei vehicles and trucks, is an exception. The pistons of a boxing engine move in a straight line.

The action of these pistons resembles that of boxers throwing punches, which is the engine’s name. Because the movements are incompatible, they result in an imbalanced and rough motion.

The other issue with this engine is that it has two engine heads. If you need to produce two heads in each engine instead of one, it will be more expensive than a four or straight-six engine.

Also read: Shifter moves but does not change gears (Here is why)

The Drawback of the Subaru Boxer Engine

There are several benefits to boxing. However, it has its cons. One of the disadvantages of this design is its wide range.

Therefore, you need to have a wide-bay engine. In addition, the piston rods can often fail.

These engines’ strokes must be short to fit a flat punch engine. The Boxer engine is the reason for many Subaru engine problems. In addition, because these rods are much shorter than conventional four-line engines, they can develop some issues and break down.

Their base is too small and cannot hold much stress. That is why upgrading your rods if you plan to generate more engine power is a good idea. The large foot makes the engine difficult to operate, too. Getting the engine on the side will be challenging if you want to change your spark plugs.

The engine is so close that it almost touches the frame’s rails. It can lead to costly repairs, and it may break during removal. Therefore, it is not DIY-friendly for a repair job.


Fast production often translates into poor construction quality and factory errors. It is why many Subaru engines have recurring issues.

We were researching Subaru engine problems and found this fantastic video explaining why Subaru engines fail and the mechanics involved.


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