It starts flashing a few seconds after start up. I've run it up to temp and the temp gauge stays a bit above half way (which it where it often gets to anyway). The header tank is about half full – is this the way it should be?? With the van up to temp I can't hear the radiator kicking in and the radiator feels cold including the pipe on the right as you look up at it – should it be warm by now?
Any idea what's up with it??

Thanks