Yanmar Tractor Fluid Types

The following is the recommended fluid types for all of the 1970's, 1980', 1990's "YM" series and "F" series tractors. This does not apply to the newer models. 

Coolant: (short answer = "universal... if you are in a bind")
The important thing about antifreeze is that you use a type that is compatible with whatever is already in there. Mixing coolant types can cause problems like increased corrosion, gelling, and sludge buildup. If you are unsure what is in there then the "universal" stuff works just fine for short term use.  It is generally not recommended for long-term use though. If you are unsure what is in there then this is a great time to flush the system and replace with a modern ethylene glycol-based Extended Life Coolant (ELC) that is nitrite, silicate, and phosphate-free. This is a major improvement over the old green antifreeze, which loses a significant amount of its corrosion protection in as little as one year. A 50/50 mix is recommended in all tractors with water pumps.  If your tractor does not have a water pump then you need to use no more than 40% antifreeze in the summer months (25% is often better) and add more antifreeze during the winter to prevent freezing. Always use distilled water to prevent mineral buildup. 

Transmission / Hydraulic System: (short answer= J20C)
The transmission, rear axle, and hydraulic system of almost all Yanmar share one common reservoir so you will want to use a Hy-Trans oil. The old tried and true "303 compatible" stuff is no longer recommended due to the actual recipe for what is "compatible" being lost many years ago (and including whale oil). Read more about that here. The correct oil now is J20C oil "JD20C compatible" for almost all climates. 

Engine Oil: (short answer = 10W30)
The recommended engine oil varies by your local temperatures but, in general, 10W30 is recommended for most of the USA. You can take a deeper dive into engine oil here.

4wd Axle Oils (short answer = 80W-90)
These axles will need a 80W-90 or similar gear oil. This stuff always smells horrible but does what it needs to do. 

Power Steering Oils (short answer = J20D or Low-Vis UTF)
Some "F-Series" Yanmars have a separate pump and reservoir for the power steering system. These reservoirs hold J20D which is a thinner version of the hydraulic/transmission oil listed above. Sometimes this oil is also called "Low-Vis UTF". Some users also report using ATF (Automatic Transmission Fluid) though it might not lubricate the sliding components as well as J20D.  

Grease Zerks: (short answer= lithium for bearings & moly for pins)
If you want to be truly scientific about what you need then you really need two types of grease. For things that spin relatively fast like 2wd hubs and mower spindles you will want a Lithium Complex type grease. These greases do better with higher speeds. For things like pivot bushings and front loader bushings you will want a "moly" grease. These types of greases do better with heavy loads but do not do well at speeds or constant rotation. I, personally, just keep two grease guns marked and loaded with the correct grease for both applications. If you really want to impress your friends you can remind them the word 'zerk' comes from the Austrian inventor who patented the unique looking fitting - Oscar Zerk.