2006 equinox Keeps running hot

I have the same problem I have a Chevy equinox 06 an at red lights or idling for a short time it starts over heating an when it hits the red an I stop it spills out some coolant the ac comes on but not that good one fan was working when the ac was competing on but the other one is not coming on at all someone said it was a piston or cylinder in the engin I told me he don’t kno wt he talking about if eny mechs have eny words for me I’d gratefully appreciate it an ima try getting a new fan system for my engin an ac