I was gettin water coming from the over flow on the header tank , but you couldnt see it because of the black cover, and it wasnt a new cap just the seal, but had new cap part no.G012A8FM1, Its worth a check it drove me mad trying to find it so i know how you feel, process of illimination, but that can work out pretty dear,migth be worth biting the bullet and going to VW, total cost on mine £90.99. inc vat, but could have been worse if i'd gone down the route of stats, seals ,hoses etc, just a thought. good luck and dont let it drive u insane .lol