My head gaskets haven't gone yet ( although they're bound to now!! ) but I was in my local motor factors yesterday and they were selling a product called steelseal. It looks like a yellow liquid and is supposed to repair failed head gaskets, warped heads and cracked blocks. I don't usually like stuff like this but they said they've had good reports off everyone who's bought it. It's not cheap though at £30 each( and you need 2 for a 4l and 3 for a 4.6 ) just wondered if anyone on here had tried it. Could save a lot of work if its any good