2001 dodge neon dohc engine 2.0 radiater cracked inside a/t oil passage and mixed a/t oil and coolant . after replacing radiater I could not bleeding air.because before thermostat opining,coolant is overflow and seems like boiling. paul in texas

Ok well there are two issues here the boiling and the potential for the transmission to be harmed by the contamination of the tranny fluid by antifreeze. First A/T fluid is not going to harm the coolant system in the least, however antifreeze in the trans. fluid will harm the automatic transmission get the tranny flushed as soon as possible , Change out the thermostat then refill radiator using 50% water 50 % antifreeze ( premixed in container) fill radiator then run the car without radiator cap add coolant as needed, put you radiator cap on and wait 5 - 10 minutes until car comes up to operatimg temp. you must observe the engine to make sure the electric radiator fan comes on after the car runs for at least ten minutes if it does not the problem is the usually the radiator fan relay or the fan coolant temperature sensor last in rare cases the fan itself. As for the air bleed usually letting the car run with the radiator cap off for ten to fifteen minutes will do it just make sure you don't remove the radiator cap when the car is hot 2nd degree burns usually hurt.