there's been a number of threads here about heating the rear area - last winter I think
I doubt the minimal pressure of the water in the heater could feed back thru the water pump into the rad, and when the engine is running, it'd just be another part of the pumped flow .... but rethink it, that's a pretty long run for the hoses - most add an under seat heater [optional on some vehicles back then] with a blower rearward .... for my project TF panel I have
a heater that came from a 60's/70's Land Cruiser I'll sink into the double wall behind the driver
Bill
