300tdi expansion tank question

Hello, I am fitting a 300tdi and autobox from a Discovery into a Volvo 6x6 military vehicle. I have a big radiator out of a Ford 7610 tractor, and ideally I would like to run it without an expansion tank. Has anyone done this with a Tdi engine ? I presume that you would put the heater return into the bottom hose and the little vent pipe from the thermostat housing into the top hose ?

Any reason not to do this ?

Thanks for your help