my truck overheated awhile back because the radiator leaked dry. the motor is not seized, I know this because the direct drive fan still turns when i try to crank it. after the incident i added coolant and there was motor oil inside the radiator... what is the best course of action? a rebuilt 22r motor is $900 but should i really replace the whole thing? what is most likely the problem, warped heads? fried head gasket?