"If you've found something that works, why change it?" Subaru has taken this motto to heart with its rugged and stylish cars powered by its tried and true boxer engines. In a world where inline fours, V6s, and V8s are industry standards, the Japanese automaker specializes solely in boxer engines.
This unique type of engine from Subaru brings about its own set of advantages as well as challenges. As an owner of a vehicle that makes use of a Subaru engine, or if you're in the market for one, keep reading to learn about what makes Subaru engines unique, where to source replacement Subaru engines, about the different Subaru engines and a few notable ones, and how to take care of your Subaru engine to ensure it performs at its best for as long as possible.
The Subaru Boxer Engines
The boxer engines used in all Subarus are flat engines with boxer configurations. This configuration derives its name from the horizontal movement of its pistons, which resembles a boxer throwing punches.
Boxer engines have multiple advantages over those with inline and V-cylinder layouts:
The flat layout allows the direct flow of engine output towards the transmission, reducing energy loss and fuel consumption.
Boxer engines have a lower center of gravity, which carries over to a lower center of gravity for the vehicle fitted with it. What this means is greater handling response for the driver.
The counterpunch of the opposite piston cancels out unwanted vibrations.
In a frontal crash, vehicles with boxer engines will be safer as they drop "below" the passenger compartment instead of inside due to a lower center of gravity.
Subaru Forester and Ascent already lead their segments in fuel efficiency, but Subaru continues to innovate. It plans to improve the thermal efficiency of its boxer engines further, aiming to achieve 45% thermal efficiency by 2030.
Sourcing Subaru Engines (OEM vs. Aftermarket)
When you purchase a brand new Subaru, it comes with an Original Equipment Manufacturer (OEM) engine made by Subaru. Engines made by third-party manufacturers and usable in Subarus fall under the "Aftermarket" parts category.
Unless the engine of your Subaru is out of production and impossible to find, we recommend investing in an original Subaru engine to return your car to its original level of performance. Because of the more stringent levels of manufacturing, you'll likely get more use out of an OEM replacement. Aftermarket engines might not only not be covered by Subaru's warranty—they could also void the warranty and even damage your vehicle when installed. Moreover, they might not even fit into your Subaru's engine bay properly. When it comes to an expensive part like the engine, it's prudent to avoid taking chances and to go with the original.
Types of Subaru Engines & Engine Series
Subaru has produced two-, three-, four-, and six-cylinder flat boxer engines.
Gasoline Engines
The EK used from 1958 to 1989 in most of their kei cars is Subaru's only two-cylinder, while the EK, applied in Justys between 1984 and 1994, is their only three-cylinder. Subaru's four-cylinders are the EA, EJ, EL, EN, FA, FB, and CB. Their six-cylinders are the ER, EG, and EZ.
Diesel Engines
Subaru only produced one diesel engine: the EE. It was the world's first boxer diesel engine.
Engines Used in Hybrid Cars
Subaru's FB20X and FB20V four-cylinder engines are used by the 2014-2016 and the 2019 and onward Crosstrek Hybrid, respectively.
Notable Subaru Engine Series
EA Series
The EA engines were used by most Subaru models between 1966 and 1994 and earned a reputation for being bulletproof. Some models have been reported to run without a problem up to 500,000 km. They came in different sizes, between 1.0L to 1.8L, and included models such as the 1.4L EA63 used in the 1973–1976 Leone and the 1.8L EA81 used by the 1980–1984 Leone and 1981–1993 BRAT/brumby.
EJ Series
The EJ four-cylinder was introduced in 1989 in the Subaru Legacy, seeing widespread usage in light aircraft and kit cars because of their ease of conversion and general reliability. It remained the backbone of the engine lineup until 2021, powering most models like the Impreza, Legacy, Forester, and more. Standing out in this series, and among Subaru's engines, is the turbocharged EJ257 that powered the Impreza STI, capable of 340 hp.
FB Series
Subaru's FB is the current generation of four-cylinders that succeeded the EJ. Compared to its predecessor, the FB has better fuel efficiency, reduced emissions, and a broader torque output range thanks to increased piston stroke and reduced piston bore. With sizes starting at 1.6L, the FB powers models like the Impreza XV from 2012 onwards and the Forester from 2011 onwards. The FB20B, produced from 2012 onward, is known for its exceptional fuel consumption of 17 km/l.
Maintenance & Care of Your Subaru Engine
To realize your Subaru engine's fullest potential, both in terms of performance and longevity, it's crucial that you pay attention and care for it properly. Given the high cost of an engine replacement, you'll be doing a favor for your Subaru engine and your wallet.
Key Routine Maintenance Tasks
Here are some simple maintenance tasks that you can do yourself to keep your vehicle in good condition:
1. Regularly change the engine oil to keep the parts lubricated.
2. Check and maintain the coolant levels.
3. Be aware of any leaks and address them promptly.
4. Replace the spark plugs, wires, and fuel filters when necessary.
Common Issues & How to Address Them
Common issues include engine overheating, which can be due to a leak in the cooling system, a bad radiator fan, a faulty water pump, a faulty thermostat, or low engine oil levels. Another is engine noises due to anything from a bearing to a timing shaft problem. Finally, Subarus are notorious for faulty head gaskets, particularly in the EJ25D, EJ251, EJ252, and EJ253.
Fixes for these will involve repairing or replacing the necessary parts or topping up engine oil. If significant damage to the engine has already occurred, you may need to replace the entire unit.
Are Subaru Engines Expensive?
While Subaru's boxer engines offer better performance and fuel efficiency, their major downside is their cost. Subaru engines are more expensive than those from Toyota, Honda, and other Japanese car brands, and they cost more to maintain because of the higher price of specialized parts and labor needed.
Where to Buy Genuine Subaru Engines Online
Brand-new OEM crate engines can be purchased directly from your country's Subaru and OEM parts retailers. On the other hand, second-hand Subaru engines can be a cost-effective alternative you can find in great condition and at affordable prices here at BE FORWARD Auto Parts.
I received the correct type of autoparts i paid. but the transportation took long