My 740 turbo diesel has been playing up since I bought it, with overheating problems. It blew a horse on the way home from buying it. It runs for hours no problem, but the temp gauge will all of a sudden head for maximum. The red turbo light comes on. When it cools down and I open the coolant tank, the coolant has gone. It has now blown the radiator. Coolant poring out on the left hand side. I don't feel like spending anymore on it as I don't know what will go wrong next. The guy who had it before said he put a new water pump on, but it doesn't look new to me. There is no steam coming out of the back, and when it runs, it goes very well. Does this sound like a head gasket problem? Or something else. Any advice would be much appreciated, as Im at the end of my tether with it.

thanks

Adrian.