The part in bold is absolutely the stupidest thing i have ever read on here. A heater core is absolutely liquid filled (coolant) and the heat from the engine is not transferred to the heater core thru the air, that is just silly. Heat from the engine moves to the heater core by way of hot coolant being pumped to it.
You don't know what you are talking about. It does not sit behind the engine, it is in the dash, you have to remove the dash to change it out. Get a service manual and read it. It doesn't get hot unless hot coolant is passing thru it. That's just how it is, sorry that you are wrong, but someone has to be. And when you say that it is not as effective as liquid cooling, you are retarded because it is liquid cooling, there is liquid coolant running thru the heater core, it is a small radiator. People even get heater core leaks, and the passenger compartment will smell like coolant, google it, your ignorance is amazing.
And of course turning on the heat helps cool an overheating car, ON A NORMAL CAR WITH A BELT OR GEAR DRIVEN WATERPUMP. On a BMW the waterpump is electric, once it is dead, it is dead and no coolant circulates, so you cant remove that heat from the engine by turning on the blower fan and setting it to heat mode. Simple physics. How can heat move from the engine, to the heater core, if the pump isn't moving the coolant, think about it, the coolant is the medium that transports the heat. Think of the coolant as a conveyor belt carrying heat. The conveyor stops when the waterpump dies, so the heat stays trapped in the engine, it can't move to the radiator OR the heatercore, the conveyor stops moving it anywhere. If it could still move coolant to the heater core when the pump dies, then the same dead cooling system would also allow coolant to pass thru the radiator and cool the engine as air passes thru the fins, but IT DOESN'T and the proof is that the car overheats. Simple physics.
Heres another one for you genius, lets say your body's heart stopped beating (your body's waterpump), can your blood still flow and carry oxygen to your brain? Of course not, your brain dies. Same thing here, the heater core can't stay hot with no hot coolant passing thru it if the electric waterpump has died. Blood and coolant are both mediums that carry things to other parts of the system. If the pump stops, then the conveyor belt stops.
Heres another interesting fact. Why does BMW put an auxillary water pump in the car..... So you can use the REST feature when the engine is not running. The car has to move the coolant to be able to create heat. If you could use the REST feature without pumping coolant, then they would not have needed an auxillary water pump. Read about it here genius....
http://www.bimmerforums.com/forum/sh...ary-water-pump
Page 640-12 of the bentley manual also confirms that the waterpump MUST run to create heat while in REST mode....
"Residual heat (REST) function allows hot or warm engine coolant to heat up vehicle interior when engine is not running . This function is available for a run-down period of approx. 15 minutes from the time ignition is switched OFF (terminal 15 OFF).
Pressing REST button signals EGM via bus system to activate electric coolant pump and circulate coolant."
So there you go, you can't have heat without moving that hot coolant to the heater core. So please go play with your toys and leave the grown ups alone.
I would just laugh at the other guy 
