First some explanation: if you don't already know, I hate electronics (when they don't work) and I hate messing with them. Fortunately my Brat's heater gets nice and warm so I'm good for now BUT.... I've owned several cars with crap/no heater at all. I know I *could* pull apart every little thing in the dash and fix tons of stuff and make the heater work just like new but I don't wanna. So... If I took a smallish heater core, used Ts to plumb it into the radiator with no pump inbetween, mounted it somewhere like the dash and had a little toggle switch activated fan behind it... would that work well?

 

The idea would be to get similar results of having your radiator inside the car, without the massive heat wave.

To get water flow there must be a pressure side and a suction side, you would plumb an aux heater into existing heater lines in series. For many years there have been aux water type heaters for big trucks and boats, you may even find one to your liking in the back of a passenger type van, or a regular type van, if the van was optioned that way. Gruman vans (alumnium "bread box" vans) sometimes come with aux type heaters, or the regular heater in them is pretty universal. They are out there, maybe more so in the north, you shouldn't have to make anything, just keep your eyes open.

If you found you needed a small water pump (to increase the water flow) a bus usually has one or two 12V booster pumps, just for this purpose, about mid way up either side (or they are availaible for boats).

Alot of alarms are going off in my head on this one...:-\

 

I saw someone do that in the back of their truck.. you know, pile the kids in the back with a fiberglass shell and run hose from engine to back too keep the kids warm while driving down the road during winter. red heater hose sticking up in the back, heater core and fan flopping around.....

 

my thought is ... what happens in an accident and causes a hose to fail and shoots coolant... you know.. instant steam kind of thing....scalding temp. and all.

 

I have had one heater core fail completely, instant fog/steam cloud in car, coolant gushing too the floor out duct and not in the face....

 

but on the positive note... could you... yea... use ,metal braded hose through penetration too connection etc...

In my past life I did alot of Hydronics, boilers, steam, radiant, infloor heat... so yea.. you can put heat anywhere using water as a thermal mass, radiator and fan to disperse heat...