Old Radiator Cap???

Hello Everyone...
I would like to know if an old radiator cap that doesn't look or fit that good anymore can make an engine run hot???
Thanks
Linda

Yes. The cap that doesn't fit right doesn't allow pressure to build up in the cooling system that raises the boiling point of the coolant so it's not so prone to overheating.
Also it would probably leak. Low coolant=very hot engine.