Rubberized undercoatings do a great job of keeping existing rust all covered up and looking sharp, but it does absolutely nothing to slow down the spread of rust and corrosion sometimes the trapped air and moisture may even contribute to rust formation as was the case with GodwinAustin.

Is undercoating a waste of money?

For those of us on the prairies, undercoating is NOT worth it if you are getting for extra rust protection. However, undercoating serves another purpose and that is to add a bit more insulation from road noise. If that's what you're after, then it's worth it. In general, it is not.

Will undercoating stop rust?

The war against rust may be ultimately unwinnable, but rustproofing and undercoating can help extend your vehicle's life!. Rustproofing and undercoating can defend against the onslaught of rust-causing road salt and brine for so long.