It just failed the hydrocarbon test and also boiled out the top of the header tank when i cracked the top off so looking like head gasket or something even worse like a crack in head or block. I don't get it though. Used all new parts and had top of block and head lightly skimmed when the negine was rebuilt. Engine built by mechanic with over 20 years experience but I still end up with problems.

I used a cometic head gasket. Whats peoples thoughts on these? Its a small turbo cos so will only ever be 300bhp max. Am I better off with another type gasket?