MG ZR: Cams & Maps

[C2K]

Your rad will have antifreeze crystals on the back no doubt. Standard radiators were absolute dog-turd quality, i've replaced them on every Rover i've owned. (220, both 214s, my ex's 214 and her VVC coupe too). I'd wager this is the cause of your disappearing coolant, or potentially a loose jubilee.

By 10 years old they're just shagged, whereas that alloy rads that Peugeot use are a god-send - mine is immaculate after 12 years and 256K.