Hot baby bird
 

I just started up my 56 bird after two years of storage and after fifteen minutes or so of idling it started to run hot. This has been a chronic issue over the years and the radiator has been replaced years ago but that doesnt seem to have done much. Any thoughts as to what could be causing it? Thermostat? Hoses?

312 engine with Ford-o-matic 2 speed auto

you might want to do comp. test to see if you have a head gasket blown or if the exhaust is getting in the water jacket another thing you might check is if there is not enough water in the coolant most are mixed at about 50/50 we all know that water evaporates and antifreeze won't. the next time you start it up smell the tail pipe if it smells really sweet or if there's white steam or smoke coming from it then you have a bigger problem. next is take the radiator out and have it cleaned and try it again just don't let it run too long or get it too hot.

I agree with grindman. Also: maybe the water pump does not pump or the thermostat does not open?

you can check to see if both things are doing what they should do just by opening the radiator cap and let it run until it warms up just to normal with the cap off of it. if the antifreeze is flowing through then the thermostat is opening like it should and the pump is working like it should as well. please let us know how it turns out