It has two clicking points. Not sure how since mine broken that bad it actually hangs loose but this weather not suitable or you can get car to 15 celcius by sheltering it and just get the replacement first it will help you out. Or buy a plastic waterpipe cap (construction market, might need some ductape to make it snug) and use a funnel with hose it is not exactly high maintenance filling point
For getting such a cap bring your measuring caliper and yes measuring in the car with such tool doesn't exactly work well but I just bought two caps and brought one of them back to the store