sounds like a crack in the block or head buy yourself a head gasket test kit that will at least tell you if its head off again or another fault.
http://cgi.ebay.co.uk/UNIVERSAL-BLOCK-TESTER-KIT-FOR-GASKETS-CYLINDER-HEADS_W0QQitemZ130364511854QQcmdZViewItemQQptZUK_Diagnostic_Tools_Equipment?hash=item1e5a54966e
thurrock handyman, March 2010