How to stop hot air from engine compartment?

kursplat said
or the heater valve in the engine compartment is not closing and letting the hot water flow though the heater core

I thought only AC cars have that valve?

Mine doesn't and it's not an AC car.

If no hood seal at the cowl hot air could be getting pushed out and into the cowl vent entering the cabin if the doors are open or not sealed or in my case just missing.