Part of the Yanmar Parts Manuals.
Strip a Yanmar 3TN66L-EUBA down to the block and you will be ordering parts within the hour: main bearings, valve stem seals, crankpin bearings, the gaskets to close it all back up. This 33-page parts catalog, Yanmar publication Y00B6331, is how you order the right ones the first time. Guessing costs real money; the wrong bearing shell or nozzle assembly means a second teardown while the correct part sits on a shelf somewhere else.
Fifteen sections cover the complete engine: cylinder block, gear housing, flywheel housing and oil sump, cylinder head, manifolds, camshaft, crankshaft and piston, the lubricating oil and cooling water systems, the fuel injection device, governor, starting motor, and generator. Rebuild sizes are listed too, including 0.25 oversize piston and ring sets and 0.25 undersize bearings.
Download the PDF, print the pages for the system you are in, and check off part numbers as the engine goes back together and runs again.
What's Inside This Yanmar 3TN66L-EUBA Parts Manual
| System | Pages | Key Topics |
|---|---|---|
| Cylinder Block | 3-4 | Gear Housing Assy, Gear Case Cover Assy, Oil Seal HTC456208, Knock Pipe, Cover, Gasket, Filler Cover, Blind Cover |
| Gear Housing | 5-6 | Flywheel Housing, Flywheel Cover Cap, Oil Seal Case Assy, Oil Seal, Oil Sump Spacer, Oilpan Assy, Oil Pan Assy |
| Flywheel Housing & Lub. Oil Sump | 7-8 | Cylinder Head Assy, Suction Valve, Exhaust Valve, Valve Spring, Spring Retainer, Valve Stem Seal, Valve Cap, Nozzle Protector |
| Cylinder Head & Bonnet | 9-10 | Intake Manifold, Suction Manifold Gasket, Air Hose, Air Cleaner, Unloader Valve, Element, Air Creaner Cover, Air Cleaner Support |
| Suc. Manifold & Air Cleaner | 11-12 | Exhaust Manifold, Exhaust Manifold Gasket, Bolt, Stud |
| Exh. Manifold | 13-14 | Camshaft Assy, Camshaft Gear, Thrust Bearing, Push Rod, Tappet, Fuel Cam Bearing, Fuel Injection Pump Cam Assy, Flange |
| Camshaft & Driving Gear | 15-16 | Crankshaft Assy, Flywheel W/ Ring Gear, Ring Gear, V-Pulley, Piston W/ Ring, Ring Set, Connecting Rod Assy, Piston Pin Bush |
| Crankshaft & Piston | 17-18 | Lub. Oil Pump Assy, Lub. Oil Pump Gasket, Dipstick Guide, Lub. Oil Dipstick, Lub. Oil Switch, Lub. Oil Filter, Oil Press Valve Assy, Oil Intake Pipe Assy |
| Lub. Oil System | 19-20 | Cooling Water Pump Assy, Cooling Water Gasket, Gasket, V-Belt, Cooling Water Pump V-Pulley, Cooling Fan, Spacer, Thermostat Cover |
| Cooling Water System | 21-22 | Fuel Injection Pump Assy, Plunger W/ Barrel, Retainer, Plunger Spring, Delivery Valve W/ Seat, Delivery Valve Spring, Delivery Valve Holder, Delivery Gasket |
| Fuel Injection Device | 23-25 | Governor Case Cover, Gasket, Governor Weight Assy, Governor Sleeve, Link Color, Link, Governor Case, Spacer Assy |
| Governor | 26-27 | Starter, Magnetic Switch, Rear Cover Assy, Starter Metal, Pinion Assy, Shift Lever Kit, Armature, Pinion Stopper Set |
| Starting Motor | 28-29 | Generator, Plate Assy, Stator, Bearing 6201ZZC3, Collar, Coupler, Flywheel, Pulley |
| Generator | 30-31 | Gasket Set, Valve Stem Seal, Nozzle Gasket, Bonnet Gasket, Suction Manifold Gasket, Exhaust Manifold Gasket, Lub. Oil Pump Gasket, Cooling Water Gasket |
| Gasket Set (Optional) & Tools | 32-33 | Gasket, (Non-Asb.), Seal, Valve Stem, Nozzle, Liquid |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Thermostat operating temperature | 71ßC | p. 20 |
| Thrust Bearing Undersize | 0.25US | p. 16 |
| O-Ring P-Type Size | 12.0 | p. 4 |
| Pipe Dimension | 12*700 | p. 8 |
| Piston with Ring Oversize | 0.25 | p. 16 |
| Ring Set Oversize | 0.25 | p. 16 |
| Pin Bearing Undersize | 0.25 | p. 16 |
| Oil Pressure Switch Setting | 0.5KG | p. 18 |
| Governor Link Length (No Color) | 88.8 | p. 24 |
| O-Ring S-Type Size | 7.0 | p. 24 |
| Wire Gauge/Diameter | 0.6 | p. 25 |
Yanmar 3TN66L-EUBA Common Problems This Manual Covers
Hard starting or no start
Air in the fuel, a worn plunger, or a tired nozzle will leave this engine cranking without firing. The Fuel Injection Device section lists the injection pump assembly, plunger with barrel, nozzle assemblies, rack, and pinion so you can order replacements by part number instead of guessing.
Manual Section: Fuel Injection Device p. 23Low oil pressure warning
A flickering oil light or valvetrain clatter usually traces to the oil pump, a clogged filter, or the relief valve. The Lub. Oil System section breaks out the pump assembly, filter, dipstick, and valve assembly with their gaskets.
Manual Section: Lub. Oil System p. 19Overheating under load
A worn cooling water pump, a slipping belt on the V-pulley, or a damaged fan will send the temperature climbing. The Cooling Water System section identifies the pump assembly, fan, V-pulley, and gaskets for the cooling circuit.
Manual Section: Cooling Water System p. 21Blow-by and rising oil consumption
Worn rings and cylinder wear show up as crankcase blow-by and oil disappearing between changes. The Crankshaft & Piston section lists pistons, piston rings, connecting rods, and crankpin bearings, the core of any bottom-end rebuild order.
Manual Section: Crankshaft & Piston p. 17Starter clicks but will not crank
When the starter drops out or just clicks, the magnetic switch, pinion assembly, or armature is the usual culprit. The Starting Motor section shows each of these as orderable parts rather than forcing you to buy a complete starter.
Manual Section: Starting Motor p. 28Burnt valves and leaking stem seals
Poor compression on one cylinder or oil smoke at startup points to the head: valves, springs, or hardened stem seals. The Cylinder Head & Bonnet section covers suction and exhaust valves, valve springs, stem seals, rocker arms, and glow plugs.
Manual Section: Cylinder Head & Bonnet p. 9Oil leaks at the sump and seals
Weeping around the oil pan, drain plug, or rear seal is common on engines that have sat. The Flywheel Housing & Lub. Oil Sump section lists the oil seal, oil sump, oil pan, and drain plug so you can reseal the bottom end in one order.
Manual Section: Flywheel Housing & Lub. Oil Sump p. 7Frequently Asked Questions
Which engine does this parts catalog cover?
It covers the Yanmar 3TN66L-EUBA diesel engine and is Yanmar publication Y00B6331. Every listing is keyed to that exact model code, so the part numbers you pull match the EUBA specification rather than a similar 3TN66 variant.
Does it list oversize and undersize parts for a rebuild?
Yes. The catalog lists 0.25 oversize pistons with rings and 0.25 oversize ring sets, plus 0.25 undersize pin bearings and a 0.25 undersize thrust bearing, so once you have measured the bore and journals you can order rebuild sizes by part number. p. 16
What cooling system parts can I identify with it?
The Cooling Water System section covers the cooling water pump assembly, fan, V-pulley, and the gaskets that go with them, which are the wear items behind most overheating complaints on this engine. p. 21
Does it include torque specs or repair procedures?
No. This is a parts catalog: part listings organized by system for identification and ordering, not a service manual. Cylinder head torque sequences, valve lash, and injection timing live in the service literature; use this catalog to have the right gaskets, bearings, and nozzle assemblies on the bench before teardown.
What format is this manual in?
You get a 33-page searchable PDF that downloads instantly after checkout. Open it on your laptop, tablet, or phone, and bring it right to the shop floor.
Is this Yanmar 3TN66L-EUBA Parts Catalog printable?
The PDF is DRM-free. Print whatever sections you need to take out to the shop. Standard letter or A4 paper works.
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