Komatsu 3D72-2F(S/N 02519-UP)

The Komatsu 3D72-2F (S/N 02519-UP) is a compact 3-cylinder, water-cooled diesel engine rather than a complete machine: naturally aspirated, indirect-injection combustion, 72 x 72 mm (2.83 x 2.83 in) bore and stroke, and 0.879L displacement, built on architecture derived from the Yanmar 3TNA72. It runs a mechanical jerk-type injection pump with no electronic engine controls, only analog warning lamps for oil pressure, coolant temperature, charge, and pre-heat. It belongs to Komatsu's 72-2 Series engine family, sharing a shop manual with the 3D75-2, 3D78-1, and 3D84-2, alongside in-family siblings 3D72-2G and 3D72-2GA. No confirmed operating weight, dimensions, or exact production-year window are documented for this -F/02519-UP suffix build specifically, and no confirmed predecessor or successor engine is on record. The serial block places it in Komatsu's early-1990s micro/mini excavator engine lineup, used across the PC05/PC07/PC12UU-class range and OEM-badged siblings such as the Yanmar C20R, Neuson 1501RDV, and Case CX23, though no single host excavator model is confirmed for this suffix.

Across the 72-2 Series, the core block, bore/stroke, and mechanical fuel system stayed constant; the letter suffixes (B, BA, C, E, F, G, GA, H, HA) mark differences in accessory fitment, such as PTO takeoff points, cooling configuration, and mounting brackets, tuned to whichever excavator or compact carrier the engine was dropped into. That shared architecture is why one shop manual still covers the whole family rather than a model-specific book. In today's used and parts market, engines like the 3D72-2F matter because they are simple, mechanically governed replacement power units for aging micro-excavators whose original host-machine documentation is often incomplete or lost. Buyers sourcing a compact naturally aspirated diesel with jerk-pump injection and Yanmar 3TNA72 parts crossover treat the 72-2 Series as an interchangeable pool, which makes correct suffix and serial-block identification the key to sourcing the right internal components.

Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.