I 100% know this isn’t the correct way.
What is the reason the heater core is behind the firewall? To keep it out of the cold?
I have a vehicle that I don’t want to dump money into. It isn’t getting hot air from the drivers side. It blows hard but it isn’t hot. I was told it was the heater core from a shop. I tried to flush the heater core twice. It didn’t seem clogged as water flowed freely (just an observation).
Can I just buy a heater core and mount it inside the engine bay instead of tearing the dash apart?
No, but it would let you drive the car until you can replace the heater core. You can buy a propane heater at most hardware stores if you need to stay warm. Be sure to open a window some…