water loss passat tdi 2002 ?

check your oil is at the correct level (near the top notch in the dipstick but not over it) if it isnt near the top, put car on flat level top up with oil untill it is level with the top notch on the dipstick, drive car and check every other day if oil level increases past the notch then head gasket is more than likely failing.
you can aslo check around the engine using a torch for leaks in all the rubber hoses if none are visable and your oil is at the correct level after say a week then check the amount of coolant in your system (the strength of the mix) it might be simple like not enough antifreeze causing the water to boil/evaporate as it passes around the engine.
lastly id say also check your radiator for leaks especially around where the metal fins join the outer frame as the last 4 i have done have leaked from there hth

gary
July 2010