[Rubble]

Originally Posted by kalbert

Like has been said already, hydraulic oil, like used in a forklift for raising the forks, is specifically formulated to not foam, can't handle the temperature or foreign substances it would contact in an internal combustion engine, and could damage the rubber parts. it's primary purpose is to take up space and secondary is to take up space. It is also a very poor lubricant, especially compared to actual motor oil which is specifically engineered to be very slippery stuff in addition to having detergents and other additives that make it resistant to heat and to carry particles of foreign material safely encapsulated to the filter where they get stuck. It's primary purpose is to lubricate and secondary is to carry garbage to the filter.
applications.

Hydraulic oil used in a hydrostatic transmission or power shift tranny is required to be a much better lubricant than engine oil.Hydro units are much closer tolerance than a internal combustion engine.Hydraulic oil must be able to absorb water,cool & lubricate parts.When I worked at an IH Ag dealership in the mid 80s,their hydraulic/hydrostatic trans oil was refined to way better specs than their engine oil.Ask anyone that works in heavy equip/Ag related repairs & they will tell you that as well.