1998 Chevy Lumina help

My car gage temp gage goes to hot back to normale three or 4 times a day my dad replaced thermastate and put new cap on it I un hooked temp scensor and it did when get to hot it never gets to boileing point the raditor into res box almost gets full but then bubbles down and the hose leading to res box leaks but I dont now if that would cause car to get hot like that or not I need help there no leaks around water pump or etc just res box gets to full never boils over so my? Is people say scenor but I dk because I un hooked it lol and it still did it when it stareted doing this the check engine light came on and stays on we had the car siunce 98 my dad replace all gaskets etc and new valve covers gaskets and stuff so yeah my dad spent weeks getting back on the road so yeah and that wasent my question my questios is if the hose is leaking would it caue the radator temp gage to jump to hot and back to normale