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 flex pipe is a pipe that conects the exhaust manifold to you exhaust so that when the moter shifts it doesn't shake the whole exhaust syster. Yes it can be the reason that you car is so loud. OR, it is a cheap way to replace a faulty exhaust pipe. Hi, I own a 1990 Plymouth laser also. The flex pipe is on what they call the J pipe. It attaches your exaust manifold to your catalytic converter. There is also a brace for the J pipe that runs from the pipe right under the manifold and attaches to your engine block. It has been known to cause a hole in the pipe where it wraps around.