I think Merope is saying that the blue coolant comes pre-mixed (not concentrate) and it should be topped-up only with more blue (pre-mixed) coolant, and not with distilled water, tap water, grey water, or anything else other than blue (pre-mixed) coolant.There are different types of water; which one are you referring to?
This coolant issue, so far this Subaru none. No loss of coolant. Othet one the OOutback. 2013 used about 1cup per week 1antifreeze bottle last me 5 years. Between that and equal parts water. My Landrover nothing, I added half a bottle of antifreeze in 8 years. Current VWtiguan 2.0 nothing.In5 years and my wife's Mercedes CLK350 nothing added in 13years.They should fill it up when they do the service. Mine does ,and they wash your car too. Right ?