A quirk of any car, when water gets hot it expands so the level will go up, providing it doesn't pour out of the filler when hot its probbly OK.

Looked over an old (think it may have been N reg) Corsa the other day and I noticed the water level when just started from cold was not visible in the header tank. When the engine was turned off (hot by this time) the level was visible at the cold level on the tank.

The header tank needs topping up!

When cold, the water level should reach the full mark. That's what it is there for.

Edited by Doc on 21/04/2010 at 21:24

I have never had to top up my own cars (it is a sealed system after all). If it needs topping up it must have used or lost some. What I find baffling is that the main dealer says this is normal (not visible when running cold and only up to the cold level when hot). Why would a main dealer with no connection say this ?

Vauxhalls should stay pretty much round the centre. Not normal and not a quirk. Could be something or nothing, a bad head gasket (very common on Vauxhall) or a bad thermostat (which aren't as cheap as they should be either).

I'd suspect it had an expensive problem as the dealer would have sorted it otherwise.