Hello people, i have a '99 golf gti 2.0 apk engine and noticed it is getting through quite a lot of oil- about 1 litre per 800-1000 miles. i've heard its a common problem with the 2.0 engine and vw say its perfectly normal? also under the filler cap is loads of yellowy sludge, which leads me to believe it is the head gasket? though haven't lost a drop of water and the engine runs fine and has done for the last 4000 miles since first noticing the sludge. there is no smoke on start up, or when driving. anyone any idea what the problem may be? cheers