Mitsubishi 4D56 Engine Specs

The Mitsubishi 4D56 is a 2.5-liter turbocharged inline-four diesel engine produced continuously since 1980, one of the longest-serving diesel engine designs still in use and arguably the most widely distributed Japanese diesel engine ever built. Over more than four decades, it has powered an extraordinary range of vehicles well beyond Mitsubishi's own lineup - the Pajero, L200, Delica, and Challenger most directly, but also, through licensing and OEM supply arrangements, the Hyundai Galloper, H100 Porter, and Starex, the Kia Bongo and Pregio, and diesel versions of the Fiat Ducato, Peugeot Boxer, Citroën Jumper, Ford Transit, Volkswagen LT, and Mercedes Sprinter van platforms, along with the Ssangyong Korando and Musso.

Across its long production life, the 4D56 has been offered in numerous states of tune, from a modest 73hp in its earliest, simplest mechanically-injected form up to 140hp in later, common-rail turbocharged versions, with torque ranging from 196 to 314Nm. Its SOHC 8-valve architecture and very high 21.0:1 compression ratio are characteristic of a design conceived well before modern high-tech diesel engines became the norm, prioritizing mechanical simplicity, ease of field repair, and tolerance of poor fuel quality and harsh operating conditions over refinement or outright efficiency.

That combination of simplicity and durability is precisely why the 4D56 has achieved such extraordinary global reach: it is genuinely capable of exceeding 500,000km in commercial and utility service with proper maintenance, and it remains serviceable in markets with limited technical infrastructure thanks to a design that predates much of the complexity found in modern diesels. That said, a working knowledge of its maintenance requirements matters for any buyer. The timing belt is absolutely critical, as this is an interference engine, and belt failure causes catastrophic valve damage - given the long service intervals some owners mistakenly assume, this remains one of the most important items to verify on a used example. Mechanical injector pump problems can become expensive to resolve, particularly if the fuel system has seen contaminated fuel over its life. Glow plug system failures are common in cold climates and directly affect cold-start performance. Later, common-rail versions with EGR valves are prone to clogging, particularly in stop-start urban driving with poor-quality fuel, and head gasket issues can develop if the engine has been overheated or poorly maintained at any point in its long service history. Turbocharger longevity, as with any turbocharged diesel, varies considerably with maintenance quality and duty cycle.