steam coming out of 996!!

[kneddy]

hi guys,i wonder if you can help.i got a 98 996 c2 6 months ago from a dealer only for it to have engine failure 2 days later!!(3 cracked bores) the dealer done a runner so was down to me.i got a new bottom end from hartec and had addspeed do work to the heads and re-fit the new engine.i have done only 50 miles when seam started coming out the back!! i had a look and there is no sing of a leak,asked addspeed they said it prob has to much water so is coming from the overflow? i let it cool and drove 10mins home by which time there was steem coming out again!! please help,could it be air trapped? or something else? i have spent £8600 and still have a car i cant drive!! a very unhappy camper!!the water level dropped first after i drove home from picking it up and they said this is quite normal and to fill it up-is there to much in the system now? getting realy fed up with this now,sorry for such a long post but you guys prob know more than most,thanks kneddy