VW will tell you that you must use their specific yellow coolant. You don't. Just use the top of the line Prestone that is for all engine types. Don't add water!! It runs on pure coolant...
Where is the coolant temperature sensor located on a 1999 VW Passat?
If you have a 1999 Passat V6, the coolant temperature sensor is located in the lower radiator hose. ...