I've got a crack in my exhaust manifold and I am exploring my replacements options (headers vs. manifold/cat combo, new vs. used); but in the meantime I'd like to patch it up. Cant weld it without taking the entire thing off (crack runs around the back). I was considering JB Weld, but I've read that that will burn away at 500-600 degrees. Does anyone know approximately how hot my exhaust manifold will get?

98 Civic DX

 

not that hot. you shoudl be worried if it gets too much hotter than 200.