170k miles auto I ran water in the radiator for two months til it boiled in the reservoir, gauge didn't show overheating. I took the thermostat out filled the radiator up with coolant, it ran good one day then overheats the next day and boils coolant then next day the reservoir is empty when I fill it up and top off the radiator it will run good for that day then boil the next Any one know what might be wrong no leaks or oil mix with coolant

 

Have you checked or replaced your radiator cap? if it cant hold pressure then the water/coolant will boil at ~212. The cooling system has to be able to hold pressure.

 

[QUOTE=colonelcorto;52003285]Have you checked or replaced your radiator cap? if it cant hold pressure then the water/coolant will boil at ~212. The cooling system has to be able to hold pressure.[/QUOTE

It fixed by its self no more problems thank you