Oil in radiator???

Ya, I'm guessin some of your buddies or maintenance guys are either playing a cruel joke or just have no idea what they're doing.

May be a leak at the head inner o-ring... least wise that's what seemed to be the issue with the '06 YZ125... by the time I checked pretty much pitting and erosion made sealing difficult. In an emergency I wrapped the inner o-ring with teflon tape which helped fill some of the voids where metal had been removed. Got us thru the season and actually similar issues happened with he '05 YZ250... Pump seal will leak into the trans which is vented to atmosphere. Leaking head gasket more often than not will leak inward toward the cylinder side when "hot" and oil will leak outward into the cooling system when cool... now this is a guess based on symptoms.... good luck.