My 97 Disco started hissing in sync with rpms so I found stripped bolt on exhaust manifold passenger side. Paid a guy $150 to rethread and replace both Mani gasket and pipe flange.......still hissing, did the whole paper in front of hiss to figure where its coming from, now worried its the head gasket, any advise?

 

have some one block the exhaust with a rag, the exhaust will back up and blow out of your leak

 

Don't Panic yet .... was the hissing coming from there originally ?? or only after changing the gasket ?? ... do what drowssap said first and we will take it from there ...