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 used JB weld on my cars radiator when I had a leak and it worked mind you the tank to fit into it and the door to get to the tank is on the outside of the house. Amazon JB Weld 8277 WaterWeld Underwater Epoxy Putty: JB Weld WaterWeld will plug or seal leaks and patch holes and s in almost. used JB weld on my cars radiator when I had a leak and it worked mind you the tank to fit into it and the door to get to the tank is on the outside of the house. Amazon JB Weld 8277 WaterWeld Underwater Epoxy Putty: JB Weld WaterWeld will plug or seal leaks and patch holes and s in almost.