Hi there

Please remember that your expansion tank was not made by Morgan motor company it’s a bought in item and the markings on it will relate to the position in terms of height above coolant level that the original manufacturer of the model it was taken from decided. It has nothing whatsoever to do with the installation in a Morgan the markings are therefore irrelevant.

When the system burps out the excess water that’s the correct level for your installation and as long as you don’t lose fluid below this level anything above it will be blown out as you’re experiencing.

Hope that helps.

BR
Colin

BR Colin
Who used to be a Spanner Juggler