I might add up to a couple of pint or so of distilled h2o.. anymore and I'd get some coolant to mix. if it goes off once more, convey it to your vendor. its very likely just evap lack of the h2o percentage of the coolant mix. glycol doesnt evap https://cars-with-spoilers-pictur70357.shoutmyblog.com/26997740/not-known-details-about-types-of-coolant-for-bmw-335i