Description

Yanmar 4TNE108, 4TNE108T Parts Catalog – OEM Factory Part Numbers for the 4TNE108

Getting the wrong part number for a main bearing or a plug on a Yanmar 4TNE108, 4TNE108T Parts Catalog job will cost you time and money. I’ve seen guys order a stud bolt off a generic aftermarket chart and end up with a thread pitch that doesn’t match the block. Then the machine sits, the customer breathes down your neck, and you’re eating the return shipping. This 23-page OEM catalog kills that guesswork. Every part number on these pages comes straight from Yanmar’s engineering team, not some third-party recompilation that swapped a bolt length or used a supersession that doesn’t apply.

Whether you’re rebuilding a 4TNE108T after a head gasket failure or tracking down an oil squirt nozzle seal for the 4TNE108, this is the document that tells you exactly which plug goes where and how many you need per engine. No aftermarket interpretation. No vague references to “similar” parts. You get the factory ID for every bolt, bearing, and seal listed by engine variant (A through F). That matters when the (A) block uses a different thrust bearing than the (C) block.

23 Pages of Factory Part Numbers – Nothing Else

Twenty-three pages. That’s it. Not a binder full of generic tractor stuff you have to sift through. Each page is a focused assembly view with a parts table that lists the reference ID, the Yanmar part number, the description, and the quantity per variant. Page 1 covers the cylinder block assembly: block assembly, main bearing caps, stud bolts, thrust bearings, seals, plugs. You see the exact screw specifications – M10x20 plated versus M10x30. Page 2 takes you through the gear housing assembly, including the cover, gasket, O-ring, and the full run of plated bolts from M10x20 up to M10x90. You need a bolt for the gear case? Find it on the table and order the right length the first time.

The catalog uses Yanmar’s own parts numbering system. That means when you call a dealer or punch the number into an online catalog, you get the genuine article. No cross-referencing a Chilton code or hoping a Chinese knockoff matches the thread depth. If a shop manual tells you to replace the main bearing upper and lower as a set, this catalog shows you the part numbers for both upper and lower shells, with over-size options like 0.25mm and 0.50mm noted in the remarks column. That kind of detail keeps an engine from seizing up because you grabbed the wrong undersize.

Cylinder Block Assembly: What the Parts Catalog Reveals

Look at the cylinder block section on page 1. The exploded diagram shows every component that bolts onto or into the block. You’ve got the main bearing stud bolt (part 7), the bush for that stud bolt (part 8), and the bolt cap (part 4). Each variant – (A) through (F) – uses the same number of those parts: 12 of each for the main bearing caps. But the thrust bearing assembly (part 15) appears twice, and the catalog shows a different thrust case bearing (part 21) that only gets one per engine. Without this breakdown, you’d buy two of everything and end up with extra parts that don’t fit.

Remarks on the page note oversize availability: (1) OVER SQR(0).50, (2)=.25PART. That translates to 0.50 mm oversize and 0.25 mm oversize bearings. If you’re machining the crank journals, you need to know which oversize to order. The catalog tells you right there in the remarks column. Aftermarket parts lists often skip these oversize details, leaving you to guess or pull a bearing from stock that may not be the right diameter.

Gear Housing Assembly: Fastener Lengths Matter – Don’t Strip the Housing

Gear housing fasteners on a diesel engine see serious vibration. Page 2 lists 26 different bolt types for the gear cover and housing. M10x20, M10x25, M10x30, all the way to M10x90. One wrong bolt length and you either bottom out before clamping or you poke through into the timing gear cavity. The OEM catalog gives you the exact length for each position. For example, part 19 is M10x70 plated, part 20 is M10x80 plated, part 21 is M10x90 plated. If you mix them up because the aftermarket list showed generic “M10 bolts”, you risk cracking the housing during torque-down.

Also note the O-ring and seal part numbers for the gear case. An oil leak at the front seal can dump lubricant onto the ground before you even start the engine. The catalog lists the gear case gasket (part 2) and the O-ring (part 5) with separate numbers. A generic gasket kit might include a different thickness O-ring that doesn’t compress enough, leading to seepage. Use the OEM numbers and you get the exact rubber compound and cross-section Yanmar tested.

Using This Parts Catalog with Your Service Manual

A parts catalog on its own won’t tell you the torque sequence for the main bearing caps or the clearance specs for the thrust bearing. That’s what the service manual is for. But when the service manual says “replace the main bearing with the correct oversize”, you need this catalog to know which part number to order. Pair this with a factory service manual, and you’ve got the full picture – procedure plus parts. I keep both on the bench for any Yanmar overhaul. It’s the only way to guarantee you’re not stopping mid-job to chase a part that doesn’t exist.

For other Yanmar engine configurations, check the Ammann Yanmar B12 B17 Parts Catalog for compact excavator applications, or the Yanmar YB271, B27 1994 Parts Catalog – OEM Factory Specs for older YB series tractor engines. If you need a larger diesel reference, the Yanmar YB301 YB351 1991 Parts Catalog – 248 Pages OEM provides deep coverage for those models.

Trusting aftermarket documentation for parts numbers on a diesel engine is a gamble. The OEM database is the only reliable source – same factories, same engineering revisions. For a broader context on why OEM documentation matters in heavy equipment repairs, read the Automotive Industry Overview and the related Automotive Industry Overview on standard practices in parts numbering.

FAQ – Yanmar 4TNE108, 4TNE108T Parts Catalog

Does this catalog include torque specs for the bolts listed?

No. This is a parts catalog, not a service manual. You get part numbers and quantities, not torque values or assembly instructions.

What engine variants are covered in this 23-page catalog?

The catalog covers five engine variants: 4TNE-108-2A, 4TNE-108T-2A, 4TNE-108T-6A, and two additional 4TNE108T-2A designations. Each variant has its own column in the parts tables showing quantities per assembly. The column headings A through F let you quickly pick the right row for your engine.

Can I use this catalog to rebuild a 4TNE108T from scratch?

Only for ordering parts. You still need the factory service manual for disassembly steps, torque sequences, clearance checks, and timing procedures. The parts catalog gives you the shopping list; the service manual tells you how to put it together.

Are the part numbers in this catalog still current for recent Yanmar production?

Yanmar updates part numbers and supersessions over time. This catalog represents a specific revision. Always verify with a dealer or Yanmar’s online parts portal for any supersession updates before ordering. But the numbers here are the original factory numbers – they have not been altered by a third party.

Stop wasting time flipping through aftermarket charts that list the wrong bolt lengths. Get the OEM breakdown straight from the source. Access the Factory Manual and keep it on your tablet or print it for the toolbox. Your rebuild will go faster when every part number is confirmed.