The Komatsu PC45MR-5 left the factory with the 3D88E-7. That is a Komatsu-badged Yanmar 88 mm three-cylinder, and we stock it - new surplus and rebuilt, in both fuel systems.
The Komatsu PC45MR-5 is a 4.5-ton class short tail-swing mini excavator from Komatsu's MR-5 generation, launched in 2017 alongside the PC30MR-5, PC35MR-5 and PC55MR-5. The MR-5 machines improved on their MR-3 predecessors with roughly 5 percent lower fuel consumption without losing performance, and added six selectable working modes, auto-deceleration and idle shutdown. These are later-emissions machines - confirm the fuel system from the plate.
ENGINE SPECIFICATION. Three cylinder, four cycle, water cooled, vertical in-line. Direct injection, naturally aspirated. Bore and stroke 88 x 90 mm. Displacement 1.642 L (100.2 cu in). Around 36 hp at full rated speed, less in machines governed lower. Dry weight approximately 341 lb (154 kg). Engine as fitted to this machine: Komatsu 3D88E-7. Production years: 2017-present. Rated output in this machine: approximately approx. 36 hp.
KOMATSU 3D88 AND YANMAR 3TNV88 ARE THE SAME ENGINE.
Komatsu's small D-series diesels are Yanmar TNV engines built under the long-standing Komatsu-Yanmar relationship and badged as Komatsu. The Komatsu 3D88 / 3D88E is the Yanmar 3TNV88: same block, same crankshaft, same 88 x 90 mm bore and stroke, same 1.642 L displacement, same architecture. If your data plate reads 3D88E-3, 3D88E-5, 3D88E-6 or 3D88E-7, that is a Komatsu-badged Yanmar 88 mm three-cylinder.
This matters commercially because it doubles the pool of engines that can be built to fit your machine. We supply both, and we set the core up with the accessories your Komatsu needs.
MECHANICAL OR ELECTRONIC - THIS IS THE ONE THING YOU MUST MATCH.
The Komatsu 3D88 spans two fuel systems and they are not interchangeable. MECHANICAL INJECTION uses a mechanical pump and governor - no ECU, no sensors, no wiring harness to match. This is what most machines in the field run and it is our standard stock. ELECTRONIC / COMMON RAIL is ECU-controlled, fitted to machines built to the later emissions standards. We carry both, new surplus and rebuilt.
The suffix - 3D88E-3, -5, -6, -7 - does not mean a completely different engine. The core is the same across the family. The suffix tells you the emissions tier, the fuel system, and the accessory package Komatsu specified for that machine. The accessory package is the part that can be changed: the bellhousing, flywheel, oil pan and sump, manifolds, alternator and starter position, pulleys, brackets, PTO and hydraulic pump drive and the throttle linkage are all EXTERNAL components. They bolt on and off, and they carry across from the engine you are removing onto the replacement core.
So the working rule is: MATCH THE FUEL SYSTEM, ADAPT THE EXTERNALS.
CYLINDER COUNT. The 3D88 is a THREE-cylinder engine, 1.642 L. The 4D88 / 4D88E is a FOUR-cylinder engine, 2.190 L. Same 88 in the name, different engine. Several PC40, PC45, PC50 and PC55-class machines run the four-cylinder 4D88E, not the three-cylinder 3D88E. Read the data plate - do not go by the machine model alone.
HOW TO ORDER THE RIGHT ONE.
Send us a photo of your engine data plate - the model number, the suffix and the serial - and tell us it is going into a Komatsu PC45MR-5. We will confirm the cylinder count and the fuel system, tell you which accessories carry over from your old engine, and quote you on the correct core in new surplus or rebuilt. If what you asked for is not right for the machine, we will say so before we take the order.