Hi, I have a 57 plate ST2 and have noticed that a small amount of coolant has started to be lost a regular intervals. If I top up to just above minimum reservoir line then 1 week later coolant will be 1 inch below this line when the engine is cold. No noticeable smells or leaks or colouration in oil or in coolant. When I look at coolant level after driving (so when engine is hot) it will be back up to minimum level (suggesting noticeable expansion of water between hot and cold). I'm starting to think that water expansion when hot has resulted in coolant discharge through reservoir overflow. I'm hoping I'm wrong! Presumably the only way to truly diagnose is through a compression test? If there is a gasket problem I could do with a recommendation as to where to go to get fixed?? (Based in London)
Many thanks.