Nevermind

I'm no expert but my experience with cars shows the only time the two would get mixed is with a blown head gasket.  The idea being that with a leaking gasket, coolant can get into the piston area and into the rest of the engine, ie mix with oil.  Not sure if our rotax engine are the same.  In my MG midget a blown head gasket showed oily blow back foam in the radiator.

Is it possible you have inexperienced students or the like who maybe put one in the wrong spot?

Bert

Ah! The Bug Eyed Fright - happy if not comfortable memories.?