03 grand am low coolant light-overflow?
 

my 03 grand am has been showing a low coolant light and then flashing off.

a couple of times we would drive for about an hour then it would blow a bunch of coolant out the overflow and onto my breaks and make it smoke.

we can fill up the coolant and it will be fine for a few days, then it does it again.

Has only actually blown it out the overflow twice, both on hot days.

but low collant light comes on frequently then flashes off.

temperate is running normal always.

I am wondering if I should try repalcing the cap, or if there is a leak I just cant see, or if thereis another problem.

Maybe the thermostat?

any advice would be great,
thanks