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.
Depending on your engine and type of vehicle, the exhaust manifold can either be a set of pipes or it can be a cast iron manifold assembly. Essentially the exhaust manifold takes the burned exhaust gases from the engineâs cylinders and ejects the gas through the exhaust system and out through the car's tail pipe.The exhaust manifold gasket seals the surface of the exhaust manifold to the surface of the cylinder head, preventing leaks in the system.Over time, the constant expansion and contraction of the components (caused by constant heating and cooling in the engine), may cause the gasket to leak.ssentially the exhaust manifold takes the burned exhaust gases from the engineâs cylinders and ejects the gas through the exhaust system and out through the car's tail pipe. The exhaust manifold gasket seals the surface of the exhaust manifold to the surface of the cylinder head, preventing leaks in the system.