Hi all, New to the forum, after a little help? Have a 2014 a3 2.0 tdi. It seems to be loosing water but cans see any leaks but does it very randomly. It will be fine for weeks then the light will come on low coolant, if you unscrew the expansion cap it will gush coolant back up to the fill level. And be fine for a while. Had the heater matrix replaced and the expansion tank. Any help would be appreciated.