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.
The intake manifold directs the air-fuel mixture in the engine to the corresponding cylinder where it is burned to produce power. The coolant flows through the intake manifold to the cylinder heads to reduce engine temperature. Expansion, contraction, and heat from the engine cause the gasket to fail. This will cause coolant passing through the intake manifold to leak. A leaky manifold gasket can also result in air being sucked through the leaky gasket, resulting in a vacuum leak and poor engine performance.