Filler Cap worries, Overheating ?

[bitsobrits]

With the stock setup (no sealed catch tank) filling the header tank (more properly called an expansion tank) above about half full will result in the system burping out coolant until it achieves its own level, again roughly halfway. My very unscientific quick check of adequate coolant in the header tank is to remove the header tank cap and see if my longest finger can touch coolant. If yes, I'm good to go.

[mtnjag]

Yep, sounds about right.

[rfs1957]

Thanks, that's rather reassuring.

If water expands about 4pc, from its densest at 4C, to its lightest at 100C, and if I fill it at 20C and run it to 80C, then that's about 60pc of it's increase, say 2.5pc.

With 18L at play that represents 450ml to spit out.

Maybe the hoses give a bit, the block and the radiator will grow a bit, and together accept a bigger volume.

So my losing 300ml from being Overfilled sounds about right?

Have I just answered my own question?

[Simon P]

Unfortunately I appear to be off-scale (although, with a nod to Peter Crespin - if he's still around - I can do the Ventoux)

Chapeau!