Does line x on rocker panels prevent rust?
 

Looking to do some body work and was wondering what does everyone think about line x on rocker panels for rust prevention?

Line x on the outside will prevent rock chips on the rockers so it will help with rust but the inside of the rockers is where the majority of rusting happens. If you use line x or por15 on the inside of the rockers you should stay rust free.

I've heard some horror stories where there was a small pin hole in the line x like a small air bubble and water got in and rusted everything underneath. I just want to fix the few small spots I have and keep her looking good for a while.

Line x or any bedliner material is a top coat. if you want rust prevention, you need to use the correct materials for that, before any Line x is sprayed on.
Now, there is a wax spray you can get at body shop supply house, that can be sprayed inside the rockers that keeps rust from developing inside. but its not a rust killer the existing rust will have to be removed first. on the outside, if there is rust already that needs to be addressed first. Depending on extent of rust depends on how the proper way is to repair. I could go on and on, but the basic thing I'm trying to explain is do it properly the first time around, and it will last a long time.