Before buying the next Subaru engine, check how good it is.
As an automobiles technician with 10 years of experience working on Subaru engines, I easily know the good ones when I see them.
I will tell you everything about the 3 Subaru engines to avoid, the few good ones to buy, and great tips to keep your automobiles running.
Table of Contents
Which 3 Subaru Engines Should You Avoid?
Avoid using these 3 Subaru engines in your automobiles
- EJ20 2.0L Engine
- EJ205/EJ207/EJ20G Engine
- EJ25 2.5L Engine
They have excessive oil consumption problems, bad pumps, and engine overheating.
Those three Subaru engines consume a lot of oil while running. The pumps develop faults a few months after purchase, and the engines overheat quickly.
Because they undergo a flawed casting process that affects the ability of the pistons to function well, the piston consumes a high amount of power, causing the engine to overheat and crash.
Also read: Are Subarus Reliable? Which Subarus aren’t?
1. Subaru EJ20 2.5L Engine
The Subaru EJ20 brand is a gasoline-powered 2.0-liter four-cylinder engine that appeared first in 1989.
EJ20’s two-liter model was the forerunner of all EJ series and replaced the old EA82 1.8-liter engine to become a better option for most Subaru models
Inside the EJ20 engine, there is an aluminum cylinder block having dry cast iron sleeves lined by the internal walls of the engine.
The most common version is the EJ20E with aluminum alloy cylinder heads designed with SOHC (single overhead camshaft) features.
EJ20 engine head has four valves per cylinder with spark plugs located at the center. The intake and exhaust valves are 36 mm and 32 mm in diameter, respectively.
The crankshaft drives the camshafts using a timing belt that requires changing every 600,000 miles.
EJ20 2.0L engines are manufactured in 125hp, 135hp, 155hp and 140 hp power specs.
Forester, Legacy, and Impreza are popular Subaru automobiles that run on EJ20 2.0L engines
Problems with EJ20 2.0L Engines
- The engine has a problem with the 4th cylinder that makes it knock most times. This cylinder is the worst and overheats when the piston or rods start knocking.
- EJ20 2.0L engine models are known to have the issue of oil leakage from the camshaft oil seals and headcovers of gaskets. Oil leakage from the gasket’s headcovers of makes EJ20 2.0L is a bad choice for oil conservation.
2. Subaru EJ205/EJ207/EJ20G Engine
The EJ20 Subaru engine was the first model with a good turbocharger.
It has cylinder heads and forged oil piston spray jets used in system cooling with low compression ratio pistons and fuel nozzles 380cc.
Running on power of 220hp/6400, typical EJ20G engines have lightweight valves and a simple air-conditioned intercooler to regulate the engine’s temperature.
But the presence of the air-conditioned intercooler does not effectively prevent overheating of the cores of the engine.
Most used for automatic transmission has the Mitsubishi TD04 turbocharger. The manual transmission models come with a TD05 turbocharger.
Impreza WRX STI and WRX sedan automobiles that use the EJ20G models have the TD05H turbocharger with boosts ranging from 0.8 bar (WRX 240hp) to 0.85 bar (STI 260hp)
Problems with EJ205/EJ207/EJ20G Engine
- A major problem with the Subaru EJ205/EJ207/EJ20G is excessive oil consumption. This is due to the stuck rings. The stuck rings are very common with EJ20. To conserve oil, it’s recommended to use high-quality fuel and engine oil.
However, the EJ20 turbo engine is more dependable than the other 2.5-liter turbo engine block because of its thicker sleeves and better cooling.
Also read: Subaru: Which Model Hold the Most Value?
3. Subaru EJ25 2.5L Engine
The EJ25 is the biggest brand in the Subaru engine series. It comes in EJ15, EJ16. EJ18, EJ20 and EJ22 versions.
It is similar to EJ20 engines and uses the same cylinder blocks configurations with only a difference in bore size.
The bore core is 99.5 mm with a stroke of 79 mm instead of 75 mm used in EJ20 engines. This makes it a better option for energy conservation and a longer engine lifespan.
Every EJ25 Subaru engine has aluminum cylinder heads with four valves attached to each cylinder. The timing belt moves the camshafts.
Generally, an EJ25 engine is equipped with a Tumble Generator Valves and MAF-sensor in the intake manifold that regulates the rising and falling of the piston.
Subaru EJ25 2.5L is popular among lovers of Forester ad Legacy automobiles.
Problems Subaru EJ25 2.5L Engine
- EJ25 2.5L engines make knocking noise just like the EJ20 engines. The knocking of EJ25 2.5L starts with the issues with the 4th cylinder. This cylinder is the hottest, and cooling is very poor here.
- There are often oil leaks in EJ25 engines, coming from the malfunctioning camshafts and loose cylinder headcovers.
Why Do Some Subaru Engines Fail?
- Most Subaru engines fail due to oil starvation.
Oil starvation occurs when some engine parts do not receive a good volume of oil to keep running.
This occurs especially when a high G maneuver is pulled, and the oil floats from one side to another without a proper lubing of the entire engine parts.
When engine parts do not get the required amount of oil, the components start eating away due to heat and friction
These parts will eventually fail and ruin the engine. The greater the friction, the more scratches, and grooves will occur in those parts.
2. The mixing of oil in coolant
Oil and coolant mix in the engine due to poor fabrication of the internal components.
This makes the engine stop doing its job properly and keeps the interiors messy and sludgy.
When the motor oil and coolant mix, there will be no lubrications anymore, and the engine’s internal parts wear out gradually.
The piston rings will stop working properly while the camshafts wear off.
In the end, the car will eventually overheat and crash the whole engine blocks
3. Coolants leaking from the outside
Subaru engines also fail when coolants leak from the outside.
This leads to gaskets failing, and the coolants start to flow out from outside the engines.
The leaking diminishes the engine’s coolant level, leading to overheating and final damage of the engine.
Are Subaru Engines Expensive to Repair Compared to Other Car Brands?
Yes. Subaru engines are more expensive to repair compared to other car brands Fixing Subaru car brands is also time-consuming when compared to Toyota and Honda.
Since there are fewer Subaru automobiles in the market nowadays due to more portable brands, finding a good mechanic is hard.
Most automobile technicians won’t master all the brands and models of Subaru hence an increase in repair cost.
Those who got an eye for Forester and Legacy must be ready to pay large sums to fix blown tires, too.
Subaru gaskets are prone to head gasket failures and overheating. These damages can cost much more to replace than other brands.
Does Subaru Make Good Engines in General?
Subaru makes good engines that blend performance, power, and reliability. Subaru engines are excellent in performance and give auto users the satisfaction they need from their cars.
Most Subaru engines run over 200,000 miles before needing maintenance for speed and reliability. Handling a Subaru automobile properly will surely improve its performance and make it last longer.
For instance, the 2021 Subaru Forester, Crosstrek, and Outback models can cover the 250,000-mile mark under proper care.
What are the Most Reliable Subaru Engines?
Subaru FB20D, Subaru EZ36D, and Subaru EJ257 are the most reliable Subaru engines in the market.
The Subaru FB20D is a naturally aspirated engine with 2.5 and 2.0-liter displacement levels.
They now have increased piston stroke and a decrease in the bore size, which enhances the engine performance and reliability
There is now a decrease in the volume of carbon monoxide and carbon dioxide emission due to a more efficient combustion system.
The new Subaru FB20D, EZ36D, and EJ257 series of engines also allow for up to 28% reduction in friction, thereby solving the problems of overheating in previous models.
How to Take Care of a Subaru Engine to Last Long?
A Subaru engine will last long when the user keeps it clean, follow the service schedule, take it easy on the engines, and regularly check the levels.
- Keep the Subaru engine clean
To protect a Subaru engine and automobiles from damages, keep it clean always
Unwanted buildups of sand, dust, salt, or organic matters within the cylinder can result in poor lubrication and overheating of the engine.
2. Adhere to the service schedule
Use the periodic Subaru maintenance schedule to care for your engines to avoid catastrophic damages.
Regularly go for maintenance and servicing so that the engineers who designed the engines can service the parts.
Always be alert for any unusual engine sounds and noose. Because different engine sounds can show the internal conditions and performance of the engine.
3. Taking it easy, the engines
Take it easy on the engines to protect and preserve the Subaru engine.
Apply brakes gently and with caution. Also, ensure that the vehicle has completely stopped before changing from drive to reverse modes.
4. Check the levels
Always check the Subaru engine oil levels to avoid the engine going dry.
Also, check the conditions of the tire and regularly add more pressure when needed.
Top off any fluids that are low following the manufacturer’s specifications.
Don’t use old models of Subaru engines such as the EJ20 2.0 and EJ20G in your cars because they will ruin you.
Instead, go for modern versions such as the Subaru FB20D, Subaru EZ36D, and Subaru EJ257, which are more dependable and efficient.
Despite the critical challenges facing most Subaru engines, such as overheating, oil leaking from the gaskets, high cost of maintenance, and excessive oil consumption, Subaru engines are generally reliable.