Car keeps running hot

I bought this car in February. The car had been sitting for a long time before I purchase it. I got it scan at Midas and they told me everything that was wrong with it. Now that it has been getting hot outside it is running hot literally take it up the street and the thermostat goes up and has never done that since I bought it. I do not know too many mechanic so I can figure out exactly what the problem is. I bought a thermostat yesterday and got it put in and it is still doing the same thing running hot. the mechanic told me I may need a new motor, but I want to be for sure that is what the problem is before I spend my money. i am just trying to figure this out and get some help. nothing leaking. I have oil in it coolant in it my air or heat does not work. I need ball joints on the driver side of my car and a tire rod on the passenger side. I do not know if that could cause it to be running hot. just need to be pointed in the right direction as what to do.