Komatsu PC58UU-3-N(S/N 20001-UP)

The Komatsu PC58UU-3-N (S/N 20001-UP) is a sub-6-tonne mini hydraulic excavator in Komatsu's ultra-tight-tail-swing UU line: the upperstructure swings within the width of the tracks, and the boom carries an extra knuckle joint so it can dig parallel to a wall without repositioning the machine. It runs a Komatsu-badged, Yanmar-built-design 4D88E four-cylinder diesel of 2.19 liters; the North America -N variant specifically uses the 4D88E-5X-BC arrangement, rated at 29.4 kW (40 hp) at 2400 rpm and EPA Tier 2 nonroad certified. Operating weight runs 5.23-5.29 t (11,540-11,670 lb) depending on spec sheet and configuration. S/N 20001-UP covers essentially the full documented production run of this -N variant, built across the mid-2000s (the broader JDM PC58UU-3 platform spans roughly 2002-2009), with a minor running change recorded partway through at S/N 20377. It was offered with canopy or enclosed cab, standard or long-arm digging geometry, and a rubber-track undercarriage with piping for a hydraulic breaker or other auxiliary attachment.

Komatsu's -3 suffix marks this as the third generation of the UU knuckle-boom family, a line that traces back through smaller PC50UU-1/-2 near-zero-tail-swing excavators before the class grew into the 58-size weight bracket. The same core layout - hydrostatic travel, knuckle-boom offset digging, near-zero tail swing - carried forward afterward as the PC58UU-5 and PC58UU-6, both still built for Asian markets on the same 4D88E-family engine under updated emissions calibrations. Komatsu did not keep pushing the true UU knuckle-boom design in North America after this generation; buyers there needing similar wall-hugging reach moved to Komatsu's MR-series mini excavators, which use a pivoting minimum-radius swing boom instead of a knuckle joint. For today's used and parts market that matters, because this -3-N machine is mechanically simple, with no turbo, no engine control module, and no exhaust aftertreatment, and because the driveline and hydraulic layout barely changed generation to generation, common wear items like filters, tracks, and hydraulic seals still cross reference across the UU run, which keeps parts support workable well after -3 production ended.

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.