add a water heater to d-4

I have a D-4 ( # 24270} and want to a water heater. I found one opening on the lower radiator hose. Looking for a place for returning to the radiator system.

Thanks

Hi cfbromm,
The other outlet or inlet is the drain on the engine block

Regards

The block drain makes a good inlet for your tank heater. On my 7U there is a small 2 bolt block off plate in the thermostat housing. It is on the same side as the fuel filter housing. That plate can be removed and a pipe bung welded in. That makes a good return as it is at the head level and will circulate through most of the whole engine. Make sure you follow directions on mounting the heater.