ok well here we go, i gotta 89 toyota pickup. a few days ago i was gonna flush my coolant system. well upon openin the overflow and the brandnew radiator, i noticed a thick layer of oil floating on top. as in like 2" think in oil. but theres no water mixin with oil. drained it to be sure and its jus as clean as can be for oil. sooooo could my head gasket still be shot even with no water in oil? it doesnt smoke or run funny at all, all lights are off and hell the lil fucker runs perfect. could it jus be all the sludge from wen radiator exploded workin thru system???