The heat in my 79' has not been getting very hot, even after warming up the car for about 10 minutes. I don't know if it is the thermostat or not but I was wanting to check it myself, but I have no idea how. Also, while I'm dealing with the heating and cooling, I would like to do a full coolant flush, which includes the radiator and heater core so that I can get the most out of my heater and my engine. I've never done anything like this but I've read and watched a lot of videos about it on the internet so I was wondering if anyone could help me, step by step, check or replace my thermostat and flush out my coolant system. I know it is a lot to ask for but I would really appreciate it. Thanks!