hi my multi started playin up she drinks water like no tommorow or stores it some where as it some times over fills its self and when i release the petrol cap it sucks in lots of air. car is a 2000 1.6 petrol 100hp standard model no chips cant seem to sorce the problem have been told it could be the head but on closer inspection doesnt look like the suspect have put kseal in the water to try and solve the problem as did have a rad leak any ideas welcomed thasnks