Header tank water up and down

For a while now, i have had the water in my header tank rise to beyond the max mark when warm or when under higher rpm.

Due to this, i just have the bottle half filled.

Its strange as the water is'nt boiling at all and i see no leaks.

Since i had the fan switch fail on me at edition last year, i swapped to the low temp neuspeed thermostat and switch.


Any idea's?

Not the pressure cap letting past is it? rather than pressurising the system its pushing air out through the cap and raising the level?

james. wrote:

Not the pressure cap letting past is it? rather than pressurising the system its pushing air out through the cap and raising the level?

Well I've tried a different cap as I thought the same. I wonder if it could be the new header tank I fitted a while ago. I'll swap that and see how things go

Yeah never know may have been dropped and have a hairline crack somewhere.

Lee,

I know they are mk2 expansion tanks but i have about threee or four here if you want to try others.

guy wrote:

Lee,

I know they are mk2 expansion tanks but i have about threee or four here if you want to try others.

Cheers man

I have spares, just wanted a nice new clean one without the switch in the top.

Lol. Picky picky. !!