All sorted. Looks like from pressure testing the intercooler there was some water sitting in there. After driving around enough its blown it out. Everything is working fine again but there is a tiny exhaust leak somewhere, it looks like the gasket on the dump pipe. Really hard to tell because I can't manage to see it, too much stuff in the way, but I was getting water droppets dropping out from somewhere there. It's definately water and not coolant so must be a slight leak somewhere in the exhaust. When i get the exhaust brackets welded I'll get them to take a look as it will be easier on a hoist.