water

PobodY

Moderators
Staff member
Because it expands with heat and contracts with cold (or rather 'without heat').
Sounds like your radiator cap is on the way out and it's not holding pressure.
 

geoff pine

Well-Known Member
What do you mean by rise and fall ? it should be at the minimum level when its cold and no more than max when hot then back to minimum when it cools down.
 

PobodY

Moderators
Staff member
Then it works and it's just the natural thermal expansion of water you're observing.

Do you want the chemistry behind it, was that actually your question?
 
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