I'd increase nearly a couple of pint or so of distilled h2o.. any more and i would get some coolant to mix. if it goes off yet again, convey it for the dealer. its probably just evap lack of the h2o part of the coolant mix. glycol doesnt evap as https://car-with-a-spoiler39405.oblogation.com/27019969/the-5-second-trick-for-types-of-coolant-for-bmw-335i