i have the same car as urs and have been a victim to.
ended up spending 50,000 remaking the whole engine .
anyways i think gunship pilots reply is the best. D16 is a open block engine.if the car overheats, u have to get the block faced as well not only the head.
if the car is building pressure, i am sorry mate.take out the whole engine, n get the block faced!
(i learnt this the hard way)