Yanmar Serial & Model Number Guide

Every Yanmar engine carries a model/serial label. Here is where to find it, what each part of the number means, and how to use it for parts, service and age.

Where to find it: the engine dataplate/decal, which carries the full model code (e.g. 3TNV70). Yanmar's own distributor identification pages show example codes but ask owners to relay the code to a dealer rather than decode it themselves.

What the number means

Worked example — 3TNV70:

Part	Meaning	Detail
`3`	Cylinder count	Number of cylinders.
`TNV`	Series	"Total New Value" — Yanmar's Stage V / Tier 4 electronically-controlled series. TNE denotes an earlier mechanical base-industrial series; TNA a legacy air/water-cooled variant.
`70`	Bore (mm)	Cylinder bore in millimeters — the figure that determines piston, liner and ring-kit fitment, not the horsepower rating.

Using the serial number

Suffix letters after the bore figure (e.g. -G for generator vs -Z for industrial use) affect parts compatibility even between engines of the same displacement — don't assume interchangeability from the bore number alone. This breakdown is corroborated consistently across three independent parts/dealer sources, not Yanmar's own site, which does not publish it; "TNM" (also seen in our corpus) is not defined by any source found. No public serial-to-build-date formula was found.

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Decode rules verified against: BaileParts, Oryx Parts, and SenseiParts Yanmar engine identification guides (aftermarket/dealer-sourced). Figures are for reference; confirm against the official documentation for your exact unit.