I'd personally incorporate approximately a few pint or so of distilled water.. any more and I might pick up some coolant to mix. if it goes off yet again, convey it to your dealer. its probably just evap lack of the water percentage of the coolant mix. glycol doesnt evap https://automotiverepairshop16355.bloggin-ads.com/50616986/not-known-details-about-types-of-coolant-for-bmw-335i