Expansion header tank question

[Gary.pb]

I am going on a bit of a journey in the van over the weekend and thought I better have a quick check of my oil and water levels. The water in the main coolant tank is fine but the expansion tank is empty. Is this normal?? I kind of assumed that it stays empty and fills up as the water heats up and needs more space. Any help would be much appreciated

Cheers

Gary

[lloydy]

when the engine is cold, fill it to the max level. Then keep a eye on it, always check when cold, if the level keeps dropping you have a leak somewhere

[Gary.pb]

what fill the expansion tank to the top? Sorry if I am misunderstanding but if that is filled up surely there is nowhere for the water to expand to.

[lloydy]

no, not to the top.. look at the tank, there is a min and max mark on it. it should be filled to this max line (we are talking about the tank behind the numberplate flap?)

[Gary.pb]

Yeah that's the one. Brilliant, thanks for that. I shall stick some water in and fingers crossed it will stay there

[lloydy]

The level will go up and down depending on pressure in cooling system. So always check it when the engine is stone cold