Hillsborough County schools get out May 25 for the summer break. ChaCha on! 7 years ago
Â· just now. Report Abuse. A cast iron manifold will expand and contract, the JB Weld will not. I think JB Weld is fantastic stuff (have some as we speak) but not for a cracked exhaust manifold.You can always check out their website: http://jbweld.net/index.php I only have experienced JB with cast though, if your manifold is another material you may get lucky.ource(s): Q: Will J-B Weld work on an automotive exhaust? A: Because of the extreme temperatures of exhaust systems, we do not recommend J-B Weld for use on exhaust manifolds and catalytic converters.
I suspect actually, that the problem is a cracked part in the exhaust. I even suggested that to International, but they'd rather replace the engine and not the exhaust pipes. I guess they have one last group of parts as suspect. Everything but the DPF, Oxygen sensor and Catalytic converter in the exhaust system.