hi I have an s type 2.7 tdi 2007/8
my coolant just disappears, uses about a gallon of water on a 50 mile run, now there are no puddles under the car, there's no steam nothing to indicate where its going,
i put a new radiator cap on and drove it 25 miles and all seemed fine except when i turned the engine off the auxiliary pump kicked in and the water level dropped to below minimum, any ideas what is going on