Mechs see a lot of things & I would still give this guy a chance to solve the problem. Some mechs say you know when you have a cracked head - won't make it down the block. However, in the diesel world we see a "micro cracked" aluminum heads on the early engines that can go for years with funny cooling system issues like erradic temperatures or high cooling sytem pressure before they finally fail. Almost always the problem is identifed as a cracked head.

I'd be interested in seeing what a pressure test of the head confirmed, but it may take a very thorough pressure test at a very good machine shop. As an added precaution the head bolts should probably be replaced. MB says they can be reused if they aren't stretched past the service limit but several mechs have had issues reusing them. Yes, the head gasket needs to be replaced. Usually it comes as a head gasket set and all the gaskets are replaced.

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Brian Toscano