it could be the thermstat, water pump,or maybe a clogged catalyst converter open the cap and see if the water is circulating in the radidiator (radiator) be careful if its hot the pressure from the radiator can force the coolent to come back up into your face and cause severe burns also see if there is coolent antifreeze in radiator also could be a problem engines can run hot with plain water usually when a water pump goes bad it water dont circulate or it starts pushing water out that little hole on the waterpump also you could have a bad cap check the pressure rating on that also when engine is hot touch the catalyst converter if its super hot its clogged try flushing out radiator could be shot to you can take it out and have it pressure tested theres a few ideas you can try out good luck