What engine oil for 1984 diesel tractor AC5015 with Toyosha CS-100 engine

[TheSeeker]

Just purchased a 1984 Allis Chalmers 5015 tractor with 284 hours on it and want to change the engine oil. The tractor is a rebadged Hinimoto C-174. The engine is a Toyosha CS-100 diesel. The owners manual says "do not use multi viscosity oil in this engine use only 30 weight oil or 20 weight oil in winter. The machine is in Central PA with temperature swings from -10F to 90F. Oil has changed a lot in thirty years. Is a modern 15w-40 or 10w-30 diesel engine oil OK or should I find some single viscosity 30 weight diesel engine oil? I do not wish to change to the lighter oil for the winter if not needed.

 

[MHarryE]

The tractor was made when multi-viscosity oils tended to "shear down" with use. They started out as lighter oil and used a viscosity enhancer to get the higher high temperature viscosity. New oils produced by quality suppliers are much more stable. Synthetics in general don't shear down. Mineral oils are much more shear stable than the were in the 80s. Therefore the 10W-30 should be very good for you as an all around oil because it is the same viscosity as the recommended oil (straight 30) at operating temperature yet will flow better than straight 20 in cold weather. On the other hand 15W-40 is also a good oil if you don't have severe cold. It is a bit heavier at operating temperature but your tractor is 30 years old and might do well with the higher viscosity. Viscosity of the 15W-40 is lower than straight 20 for those cold starts.

 

[3930dave]

While it is wise to pay attention to fluids, I'll second Harry - It would be hard to go wrong with most modern oils from a quality brand. Oil specs have changed quite a bit, just in the last decade.

Personally, for Winter, I prefer a 5W40 diesel oil - starting is much easier than 15w40. Since the tractor has sat quite a bit, I'd be tempted to run a conventional 15W40 this summer, then short change it and the filter before winter.

With your low operating temps, I'd run 10W30 year round over 15W40. Shell now lists a 10W40 in their T5 offering.

Shell Rotella® Products - Shell Rotella

T6 in 5W40 is widely available, and commonly used by many as a fleet oil. I don't sell Shell .....you can't go much wrong with any known brand.... Mobil, Schaeffers, Amsoil.......

Rgds, D.

 

[Gary Fowler]

I like the price on the Shell full synthetic Rotella T6 in the 5W-40 which is good for almost all North America temperatures from low to highs. One brand, one type for all my engines whether diesel or gasoline. I used to buy one oil for my autos, one for lawnmower, one for motorcycle, one for diesel tractors and possible different grades in winter than summer, but now the T6 meets all my needs in the one oil. It is great that it has the high detergent /additives for diesel but still good for gasoline engines.