Subaru Impreza engines

The Subaru Impreza has become an icon of the compact class since its introduction in 1992, offering a distinctive range of engines with boxer engines across five generations. Each generation has brought new technologies and the signature Subaru sound, with a constant focus on reliability and all-wheel drive.

Subaru Impreza engines: Generation I (1992-2000)

The first Subaru Impreza generation established the brand as a serious competitor in the compact segment and was characterized by robust but still relatively simple boxer engines. With proper maintenance, mileage easily reached 250,000 to 350,000 kilometers, whereby the atmospheric engines were considered to be particularly durable. Typical repairs were usually due between 150,000 and 200,000 kilometers - mainly cylinder head gaskets and water pumps. The absolute top engine of this generation was the EJ20G Turbo with 211 hp from the WRX, which optimally combined power and reliability and laid the foundation for Subaru's motorsport successes.

Subaru Impreza petrol engines: Generation I (1992-2000)

The Subaru Impreza gasoline engine range included various boxer engines from 1.6 to 2.0 liters. The entry-level EJ16 engine with 1.6 liters produced 90-95 hp and was considered economical but weak-chested. The popular EJ18 with 1.8 liters offered 103-110 hp and proved to be the most reliable engine of the generation. The Subaru Impreza engines in the 2.0-liter class were divided into atmospheric (EJ20E/EJ20J with 125-135 hp) and the legendary turbo versions. The EJ20G Turbo with 211 hp dominated in the WRX and was later joined by the even more powerful EJ20K with 280 hp in the WRX STI. These early Subaru Impreza turbo engines occasionally suffered from cylinder head gasket problems, but were otherwise very robustly built.

Subaru Impreza diesel engines: Generation I (1992-2000)

Diesel engines were not available in the first Subaru Impreza generation, as Subaru relied exclusively on boxer petrol engines at that time.

Subaru Impreza engines: Generation II (2000-2007)

The second Subaru Impreza generation marked a further development of the proven boxer engine technology with improved electronics and exhaust gas purification. Most engines of this generation reach 200,000 to 300,000 kilometers with proper maintenance, whereby the atmospheric 2.0-liter engines are considered to be particularly durable. The main problems continued to occur with the cylinder head gaskets, particularly in the turbo engines between 100,000 and 150,000 kilometers. The absolute highlight was the EJ257 with 300 hp in the STI - a technical masterpiece with forged pistons and a reinforced block. For the first time, there were also weaker turbo variants for the European market.

Subaru Impreza petrol engines: Generation II (2000-2007)

New engines were added to the Subaru Impreza petrol engine range. The proven EJ15 with 1.5 liters and 105 hp served as the entry-level engine, while the EJ20 covered the mid-range with 125-140 hp. Among the Subaru Impreza turbo engines, the EJ205 with 211-230 hp dominated the WRX, proving to be more reliable than its predecessor. The top-of-the-range EJ257 engine with 2.5 liters and 300 hp in the STI offered brutal power, but was prone to overheating problems when driven in a sporty manner. These second-generation Subaru Impreza engines suffered less from cylinder head gasket problems, but occasionally had problems with the injection valves.

Subaru Impreza diesel engines: Generation II (2000-2007)

In the second generation, Subaru also stuck with pure gasoline engines and did not offer any diesel alternatives.

Subaru Impreza engines: Generation III (2007-2011)

The third Subaru Impreza generation brought with it a complete redesign of the engine range and introduced smaller displacement variants for the first time. This generation is considered a transitional period with mixed experiences - while the new 2.5-liter engines offered more torque, they initially showed teething problems. Mileage dropped to between 180,000 and 280,000 kilometers as the new engines became more complex. The early 2.5-liter engines in particular often required repairs to the cylinder head gasket between 80,000 and 120,000 kilometers. The best engine of this generation was the revised EJ255 with 230 hp, which had largely solved the problems of its predecessors.

Subaru Impreza petrol engines: Generation III (2007-2011)

The Subaru Impreza engine range was fundamentally revised. The new EJ20X with 2.0 liters and 150 hp replaced the old atmospheric engines, but proved to be less reliable. A new addition was the EJ25 with 2.5 liters in various configuration levels: atmospheric with 173 hp and as a turbo version with 230-265 hp. These Subaru Impreza 2.5-liter engines offered significantly more torque, but suffered from the notorious cylinder head gasket problems of the early production period. The EJ255 Turbo with 230 hp developed into the most reliable turbo engine of this generation following its revision in 2009. The top-of-the-range STI continued to receive the EJ257, now with 295 hp.

Subaru Impreza diesel engines: Generation III (2007-2011)

For the first time, Subaru also offered a diesel engine - the EE20 with 2.0 liters and 150 hp. However, this Subaru Impreza diesel was purchased from Isuzu and did not fit in with the brand's boxer philosophy. It proved to be uncharacteristic and had problems with the fuel injection system.

Subaru Impreza engines: Generation IV (2011-2016)

The fourth Subaru Impreza generation focused on efficiency and suitability for everyday use, at the expense of sportiness. Most engines reach 220,000 to 320,000 kilometers again with proper maintenance, as Subaru had fixed the teething troubles of the third generation. The notorious cylinder head gasket problems were largely eliminated thanks to improved materials. Typical maintenance work was required between 120,000 and 180,000 kilometers - mainly the water pump and timing belt. The best engine of this generation was the revised FB20 with 150 hp, which optimally combined reliability and moderate power.

Subaru Impreza petrol engines: Generation IV (2011-2016)

The Subaru Impreza received completely new FB (flat-box) engines with a displacement of 2.0 liters. Depending on the market, the FB20 produced 150-160 hp and was characterized by low fuel consumption and high reliability. These Subaru Impreza engines used direct injection for the first time and were significantly more economical than their predecessors. Turbo engines were no longer available in the regular Impreza - the WRX was split off as a separate model. The FB20 proved to be one of the most reliable Subaru engines ever, with only occasional direct injection problems due to coking.

Subaru Impreza diesel engines: Generation IV (2011-2016)

The diesel engine was discontinued after the third generation as it did not fit Subaru's brand philosophy and found little demand.

Subaru Impreza engines: Generation V (2016-today)

The current fifth generation Subaru Impreza relies on the proven FB engine family with improvements in efficiency and emissions. As this generation has only been available since 2016, long-term experience is limited, but the first few years show promising reliability values. The engines are expected to reach 250,000 to 350,000 kilometers with proper maintenance. The top-of-the-range engine is still the FB20, now with 156 hp, which has become even more efficient and reliable thanks to continuous improvements. For the first time, there is also a hybrid version with the e-Boxer system.

Subaru Impreza petrol engines: Generation V (2016-today)

The current Subaru Impreza continues to use the proven FB20 with 2.0 liters, now with 156 hp and improved direct injection. This Subaru Impreza engine has been continuously developed and is considered one of the most sophisticated boxer engines ever. The problems with direct injection have been minimized through improved software and cleaning cycles. In some markets, there is also a smaller FB16 with 1.6 liters and 114 hp as an entry-level engine.

Subaru Impreza hybrid drive: Generation V (2016-today)

From 2018, Subaru introduced the e-Boxer system, which combines the FB20 with an electric motor. This Subaru Impreza Hybrid variant offers 150 hp system power and significantly reduced fuel consumption, but is technically more complex.

Conclusion: The best Subaru Impreza engines of all generations

The development of Subaru Impreza engines shows a clear evolution from the robust but thirsty early boxer engines to efficient and reliable modern powerplants. While the legendary turbo engines of the first two generations ensured motorsport success, the current FB engines impress with their suitability for everyday use and longevity. The characteristic cylinder head gasket problems of the early years have been successfully rectified.

• Best Subaru Impreza gasoline engine:

The FB20 (156 hp, Generation V) combines modern technology with proven boxer reliability and offers the best balance of performance, consumption and longevity.

• Best Subaru Impreza diesel engine:

Subaru only offered a diesel engine for a short time, but it was not recommended and did not fit the brand philosophy.

• Best Subaru Impreza hybrid engine:

The e-Boxer with 150 hp system output offers modern efficiency with proven Subaru technology, but is still relatively new on the market.

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