It doesn't answer your question about warranty but Project Farm does a great job testing things and stuff. Here is an older test of several undercoatings.

 

Thanks for the product reviews. Interesting stuff, particularly the focus on new and rusted metal. Seems Fluid Film did pretty well, and probably the only product I can get done locally outside of Krown.

 

The other note from the video is how easily the fluid film comes off. I really don't think if would have any negative impact to your warranty because of how easily it can be removed vs some of the heavier rubber like undercoatings.

 

My question is this: has anyone had trouble with warranty coverage when having rustproofing done outside that offered by the dealership? I think FluidFilm is quite unobtrusive, even though it needs to be done annually it still seems a good option.

 

Thanks. Duly noted.

 

Intrigued I looked into the Feynlab Industrial for under the body and they have a video explaining their process, which includes dry ice cleaning of the underside before spray application. But what I'm not seeing is a lot of real world long term experience from people who have used it. Every once in a while someone asks about it in a forum and nobody replies.

 

Thanks. I'll give it a look.

 

There is more info on their web page here:

Technologies

Explore FEYNLAB's innovative Self-healing ceramic nano coatings with smart memory polymers that recover their original state when heated.

www.feynlab.com

Scroll to bottom right of page for address & telephone number.
I recommend calling them to ask about evidence on research regarding testing and longevity performance of their under body coating. I called them last year to confirm validation of my installer etc. Testing is a basic Material Science activity. They were easy to talk to. Then post their reply here.

 

Looks like a good solution but not available in my region of canada.

 

My experience = installed November 2024 on 2024 Crosstrek Limited. Still looks super clean after 10 months & 12,000 km. Last Subaru lasted 23 years. It had a bitumen based rust control coating. After donkey years it started as one might expect to flake off. Perhaps gravel impact & age. Many oil based coatings I understand cannot be used on exhaust pipes, muffler & catalytic converters due to heat. The Feynlab underbody coating does not have this problem which was another reason why I used them.

 

Have you researched aftermarket vs OEM undercoatings in general? Last time I did that OEMs won hands down.

 

OEM = “Original Equipment Manufacturer”. AFAIK Subaru does not make any under body coatings. If they use some, others will have made it for them to/for their specs. If you live by the Ocean or in a Rust Belt area with roads Salted during Winter Months, you will want an extra later of protection to inhibit rust. If you have done any material science research please re-post it here. BASF as one example, manufactures a range of clear top coats for painted surfaces that are sold too & used by many EU Car manufacturers. Henry Ford for Model T cars purchased all his black pigment powder from Japan.

 

I'm referring to the rust protection applied during manufacturing of every new motor vehicle sold in the U.S. Just a few years ago, the consensus was that every aftermarket coating applied on top of that trapped or let moisture in, resulting in corrosion revealed only after it became serious. I don't know whether newer products have overcome that problem; I'd repeat my research before applying anything over the factory coating, especially if I still lived in upstate New York, where at that time roads were salted about 6 months of the year.

 

I heard the same thing - that modern cars are designed to better resist corrosion, using plated metal, better primers and paints, sealant where necessary. But like any blanket statement, it may not be absolutely true in every case. I think it is true that modern cars don't rust out as bad as cars used to, but they aren't completely immune to rust.

This guy made a video this year about a couple of 7 year old trucks, one coated one uncoated. Now we can't take every youtube video as gospel, so take it as just one data point, not necessarily applicable to all newer vehicles under all conditions. For example I live in Hawaii with a lot of salt air and I've never had to undercoat my cars and I've never had underside rust. But we don't have salted roads. In contrast, if I buy a stainless steel BBQ, even 304 stainless, it rusts if left uncovered. For this video you apparenly have to open it in Youtube not in-line in the forum.

 

Yeah, the evidenced overall is that Fluid Film works, and is a good solution in parts where you really need to address salt on the roads. I ran it by service at the dealership regarding warranty, and they had never heard of it but said, sure, do it, looks good, just make sure it doesn't interfere with wiring etc. Never had to deal with warranty issues before so would like a bit more affirmation from more than one person. Not sure if independent undercoating is a kind of modification.

 

The only way that it would interfere with the warranty is if the product can be reasonably blamed for the problem.

For example if thick undercoating clogs the drains in your door and the doors flood water into your carpeting, that won't be covered by the warranty.

So just think about what could go wrong because of undercoating and those things wouldn't be covered if it was deemed to be caused by the undercoating.

So if your car door drain is defective and undercoating isn't what clogged it, then the undercoating wouldn't affect warranty claims about that.

In the video there was some mild swelling of rubber bushings, probably not an issue, but if it did cause an issue the warranty wouldn't cover that specific issue.

 

Thanks. That gives me more insight.

 

Thanks. That gives me more insight.