Komatsu 4D98E-1A-TR(S/N 00101-UP)

The Komatsu 4D98E-1A-TR (S/N 00101-UP) is a bare industrial diesel engine, not a complete machine. It is a vertical inline 4-cylinder, water-cooled, naturally aspirated diesel of 3.318 L (3,318 cc) displacement, with a 98 x 110 mm (3.86 x 4.33 in) bore and stroke, mechanical inline fuel injection, and indirect swirl-chamber combustion. Net rated output per the factory shop manual is 48.9 kW (65.7 hp) at 2,400 rpm, with maximum torque of 215.7 Nm (159 lb-ft) at 1,700 rpm; dry engine weight is 225 kg (496 lb). It belongs to Komatsu's shared 4D94E/4D98E mechanical-diesel engine family and was factory-fitted across several different Komatsu host platforms, including small crawler dozer/tractors, mini and midi excavators, a wheel loader line, forklift trucks, and a backhoe loader. No single confirmed host chassis ties specifically to this -1A-TR suffix and 00101-UP serial break, so this engine is treated here as a component power unit sold and serviced across a multi-machine parts ecosystem, not as one machine's own drivetrain. Komatsu does not publish an exact production date range for this specific suffix; it belongs to the pre-electronic, purely mechanical era of this engine family, ahead of the ECM-controlled diesels that later replaced it across Komatsu's compact equipment line.

Within the 4D98E-1 engine family, Komatsu issued several closely related sub-suffixes, including -1A, -1AD, -1D, -1C, and -1FB alongside this -1A-TR build, all covered by the same factory shop manual and differing mainly in accessory fitment and application tuning rather than core architecture. Komatsu also built a turbocharged S4D98 variant of this block as a separate badge, but nothing ties a turbo build to the TR suffix specifically, so it should be treated as naturally aspirated unless a dealer confirms otherwise on a given unit. Because this engine spans a wide range of host machines rather than one dedicated chassis, it sits at the center of a broad rebuild and parts market: buyers sourcing a replacement or core engine for a small dozer, a mini or midi excavator, a compact wheel loader, a forklift, or a backhoe loader may all be shopping the same engine family, which keeps demand for gaskets, injection components, and overhaul kits active well after any single host machine left production.

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.