I'm thinking about undercoating my 2015 EX to prevent the undercarriage from rusting out.

Good idea or bad idea?

 

From what I have read about undercoatings, they are the worst thing as most of the time, they end up trapping the humidity near the metal.


Anti-rust grease or oil is a better bet.

 

Thanks.

I'll avoid any Undercoating.

But would still would like to know the best way to protect the undercarriage from rusting.

 

If your car is currently clean/non-rusty underneath, I honestly think the best option is regular washing of the undercarriage, especially in the winter. I use a combination of a pressure washer with some wand extensions and elbows along with plastic ramps to raise each end of the car in turn. Pay special attention to any "traps" that collect salt and debris (e.g., the inner lips of the fenders). Sometimes I use my foam cannon first, but often it's just plain old water.

When it hits 35 degrees in the winter you'll find me shivering in the driveway while spraying underneath the car. If your situation doesn't allow DIY washing, there are fancy car wash places with overpriced wash undercarriage wash packages on every corner. In my case, I wanted an electric pressure washer (for washing all sorts of things) and realized that it wouldn't take too many trips through our local car wash cartel to pay for the pressure washer so it was an easy decision.

My second option would be something like Fluid Film. I used it a few years ago on my wife's car and it seems to be working. Probably needs to be cleaned off and reapplied before next winter. Watch some Youtube videos and see what you think. The key is that anything you spray under the car has to either dry completely (e.g., water from pressure washer) or completely seal the metal from oxygen, moisture, and salt. As the video above illustrates, trapping moisture (or even worse, salty moisture) against metal is way worse than leaving the metal exposed to the environment in the first place.

 

I'm definitely going to do an undercarriage wash.

I'll talk with my Honda Service Tech about what undercarriage protection is best.

I'm avoiding Ziebart after watching the video link.

 

I agree fully with the above two responders. Rust proofing will always let some water in but that water is then trapped. This causes the metal to rot. This is why Ziebart is no longer a large company. It just doesn't work like you'd think it should.

Regular undercarriage washing is key to keeping control of rust if you live in an area that salts the roads to prevent ice. Tried and true.

 

+2

I am using a similar product called Surface Shield (made by the Blaster Corp., makers of PB Blaster penetrating oil). This is my first car I've tried it on, so I don't have any results yet LOL. It's a lanolin-based spray-on substance and it smells exactly like wet topsoil. Anyway, i did one application back in November and soon I will wash the underside of the car and give it another good coating. Fingers are crossed!

 

I used this as well as reviews of it's longevity are looking good. I will likely apply it on a yearly basis right before the snow falls to ensure lasting protection.

 

When I bought my 2010 Fit new, I immediately had it rustproofed (and they didn't drill any holes to do it). I mainly had it done to make the car quieter, which it did somewhat. Never had any rust problems here in Northeastern Ohio, where we use plenty of salt. But I also had the undercarriage washed as often as possible, when temps got over freezing-no point when it's below because the salt doesn't do anything much then.