What is the difference between lubricating oils and lubricating fuel oils?

Question

what is the difference between lubricating oils and lubricating fuel oils

Answer 1

Lubricating oils are specifically for lubricating. Some examples are 3 in 1 oil, 5W30, 10W30, 10W40, SAE 30, etc.

Lubricating fuel oils are oils used primarily for fuel that have additives to aid in lubricating valves, pistons, etc. Examples are Diesel fuel and some types of Kerosine.

Answer 2

>> what is the difference between lubricating oils and lubricating fuel oils

Lubricating oil are specifially designed for that purpose.  Engine oils have additives to prevent sludge build up, viscosity modifiers, friction modifiers.  They are not designed to burn cleanly.

Fuel oils, are design mostly to burn cleanly.  They lack all the additive for good lubrication.

Good Luck...