Top fill blowing it's lid

Hi going out my mind I have a top fill rad on my gti when I fill up with water/antifreeze I run it with the cap off then as the water rises to the top then I put the lid on and the pipes go hard then the gauge goes to 3/4 then blows the seal on the flange on the matrix pipe on side of block done this twice so changed o ring on the flange and changed thermostat even thou I tested the old and worked fine there is too much pressure in the system any ideas before I need a re mortgage for all the antifreeze  I'm getting throu 

top fills are always going to expel water until the level drops, that's why manufactures started fitting expansion tanks.

head gasket gone?
Bert

No oil in water or water in oil May go and get a new rad and use an expansion 

http://www.vwgolfmk2.co.uk/viewtopic.php?f=37&t=14913

Cheers pal the only thing I can't check is pump and blocked rad as I have no expansion I'm top fill so dont get a jet of water when I rev? Any thoughts 

yeah that bit you'll have to ignore, just check everything else and follow the bleed guide, if the lower hose gets hot as well as the 2 matrix hoses you can be pretty sure the waterpump is ok. then once the stat is open feel the radiator it should gradually warm up all the way along, if it stays cold at the far end its clogged

Are all the hoses getting hot ? if yes then it sounds like a headgasket has gone and is pressurising the system. if the head gasket has gone around the bores the water system can be pressurised, and not mix water with oil and oil with water. thats my bet if its blowing out flange seals

sounds like head gasket, i used a topfil on my 20vt and to make it easyer to fil the system i drilled a 5mm hole in the thermostat so it filled the engine side also

Sorry I havbt replyed been real busy with work but will be after advise soon