Hi Steve!
I had too a lot of problems with my p38 dse bmw diesel range rover...........It started with the radiator.......changed for a new one and still overheating. then ordered the water pump, thermostat, changed everythi9ng.....still was overheating.................I was thinking on the whorst!!!!! But there was no oil in the water and no water in the oil....and nothing comming out of the back pipe......didn´t know what to think!!!!
Do you knor what it was in the end....?!!!!! Thae viscous cuopling unit..........I Fixed it so it was full blocked....It makes a lot of noise but doesnt overheat......(I´ve allready ordered The unit to england!)
Hope this help you to think and go over the complete system thing by thing.....go over everything and make sure it´s ok!
My temp gauge use to go nearly up to red when I went for a ride (but never on the red and never the light on!). As soon ass I went down hill the temp went down.,
hope it help!!!
Adal Trujillo (Canary Islands.Spain)