Komatsu D50A-16(S/N 65001-UP)

The Komatsu D50A-16 (S/N 65001-UP) is a mid-size crawler dozer in the roughly 11-12 tonne class, built for grading, land-clearing, and general earthmoving. It runs a naturally aspirated Komatsu 4D130-1C inline four-cylinder diesel rated about 82 kW (110 hp) at 1900 rpm, through a mechanical direct-drive transmission (4 forward, 3 reverse) with multi-disc steering clutches and external band brakes rather than a torque-converter power shift. Operating weight for the standard narrow-shoe track configuration is about 11,880 kg (26,191 lb); wide-shoe and low-ground-pressure swamp siblings built on the same serial block carry wider undercarriages and different weights, so exact weight varies by configuration. Komatsu built this D50 dash-16 generation roughly from the mid-1970s into the 1980s, positioned between the smaller D50A-15 predecessor and the six-cylinder D50A-17 successor that picked up the nameplate afterward. Standard fitment is a power-angle-tilt hydraulic dozer blade about 3.75 m (12.3 ft) wide with roughly 2.8 m3 (3.7 cu yd) capacity, and a single-shank parallelogram ripper was the class-correct rear attachment.

Across the D50 dash-number generations, Komatsu scaled engine and chassis together: the D50A-15 predecessor used a smaller four-cylinder engine at a lighter operating weight, while the D50A-17 successor stepped up to a six-cylinder engine and a heavier chassis. The D50A-16 sits between them, keeping the mechanically governed 4D130-1C engine and an all-mechanical driveline with no electronic engine controls or diagnostic codes; a technician reads the analog ammeter, oil pressure, and water-temperature gauges plus the mechanical air-cleaner dust indicator directly against factory troubleshooting tables. That simplicity is a big part of why the machine still circulates in the used and parts market today: no ECM to fail, a driveline a competent shop can rebuild with hand tools, and an engine with a reputation for outlasting the steering clutches, brakes, and undercarriage around it. Buyers and rebuilders now are mainly chasing undercarriage wear, steering clutch/brake condition, and hydraulic control-valve wear rather than engine failures, which keeps this generation working as a low-cost grading and pushing machine long after newer electronic dozers have taken over higher-production work.

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.