My Roadster from 2005 still has the original brass radiator. Well metal anyway. What I did soon find out was that the thermostat opened really late. Having always being used to the top hose thermostat, this was a new experience. The early flow was from the small bore pipe from the top of the radiator, through the header/swirl/level tank, then the heater matrix and picking up the flow from the heat exchanger at the oil filter. On cold days, the bottom hose stays cold for a very long time. The temp gauge is usually rock solid and in the 85/100 range. However, on the NC500 there was a single occasion, on a slow climb, single track, quite high up when It behaved unusual by climbing to over 110, and staying there for several miles. On the descent, it dropped slowly back to normal, and never repeated so must have been just those circumstances.
My GDI with Sifab radiator runs much cooler than before, but the fan still kicks in at 100. The heater is less capable than before, but good enough!
