takes the heat away from engine low coolant??
Car overheats, your heat in your car stops working
Your question is not clear...
when you turn the heat on it comes out of the motor compartment in to the car,, further cooling the engine. A good thing to know if your car is running hot: turn the inside heat on full blast to help cool it down some.
No.
If it overheats at speed, but cools down when you slow down, the problem is likely a head gasket. Combustion gasses are leaking into the cooling system, adding bubbles (which take the place of coolant) and extra heat. Slowing down means the engine is spinning slower, and less combustion gas gets into the cooling system.
your cooling fan is not operating correctly
You could be leaking coolant, your blower fan might not be working, etc.
Yes, they should both come on.
your car overheats. Your oil is not going through the cylinders creating lots of heat
Be sure the thermostat is not installed backwards.
Each car overheats at a different temperature you need to look up and find out on the internet
Its convection.