If its blown a head gasket before its overheated. The head will be warped, even more so because its alloy. You need to machine it flat and get it crack tested. Water is either getting in through the gasket or a crack in the head.

You also definately need to tourqe the head and check valve clearnces, they might not be noisy but they could be to tight and you will burn a valve.
Then you need to look at why it blew in the fist place, possibly get your radiator cleanned.