i have a 92 seville with 200k nothing wrong with it but it overheats to 260 in mins i changed the thermostat and still does it the fans work and so does evey thing else but the radiator stays cold what could it be

 

Water pump, head gaskets, plugged radiator just some possibilites

 

if your not loosing coolant, the radiator is staying cold, I would try the water pump.

 

not losing collant and i was messing with it for 3 hours tonight letting the air out the system run it with the cap off and let the bubbles come out till it gets hot then keep doing it for 3 hours it still has air in it i cant understand how no leakes or nothing

 

If you are having bubbles after 3 hours it sounds like blown head gaskets or cracked heads. The cold radiator might be a bad water pump although I have only seen it happen 2 times in 30 years but it could have overheated because of that and blown gaskets as a result.

 

I would say more than likely a head gasket. Especially if you keep getting air coming our of the radiator. You should be able to take it to a local shop that you trust and they can test the head for leaks in the head gasket. Otherwise if you were not getting air bubbles I would point towards a water pump.

 

but the coolant level isint dropping and the oil dosent have coolant in it

 

let's start with the simple stuff. if it was running fine b4 you changed the thermo maybe is there a chance you put it in upside down. the heat sensitive spring needs to be pointed down into the head so the heat can get to it or it wont open.