I have a 2010 VW Golf TDI, with 23000km on it when the coolant warning light came on. VW service department told me it's normal to have to top up the coolant. Had to add 200mL just to get to the min level mark. I'm surprised by the amount of, as they said, "evaporation". The warning came on while away on a trip. The level was below the prongs in the coolant reservoir. The coolant was cold because it occurred after starting the car one morning. I found a NAPA parts store and bought some G12 [Pentofrost SF] (couldn't get G12+ or ++ [Pentofrost ++]) and added a 50/50 mixture with water. Added 200mL to the min level. Once back from the trip, took it into a dealer. I wanted them to check for the tell tale signs of leaks...the G12 leaves behind white crystals at the point of the leak. They found no leaks, but topped up the coolant to the max line and mentioned it's normal to have to top up. I was surprised by the amount of top up for only 23000km! If the coolant system capacity is 5.2L, then this is more than 5%.