Originally Posted by juliol
Hey porkchopsandwiches, that is a good Idea, removing the rear heater and installing it underneath the bus for auxiliary radiator.
I have done that on a few of our rides here on the farm.
The best one is the tree spade truck. It always over heated due to the fan not pushing enough air through the smallish rad while sitting stationary digging a tree, revved up.
So in a pinch I used two of the rear heater units out of my first bus plumbed into the heater lines. Never heated up again.
The hottest place to draw hot coolant from on a 5.9 Cummins is off the back of #6 piston. This is part of what helps the 5.9 cummins engine in buses last as well as they do, compared to the same engine in a dodge truck. Dodge trucks never pulled coolant from #6 piston.
There are also ports for more lines behind the thermostat, coming directly off the engine block on the front of the engine.
Manny rear engine buses have a 12 volt coolant pump plumbed into the heater lines. This ensures that the flow is sufficient to carry the heat needed with all the added restriction of heater cores, long lines, 90% elbows, ect.
The 12 volt pumps can be set to trigger, and start pumping by the same system that starts and stops a electric fan on a automotive radiator.
That same system is what also triggers the fans on the bus heaters.