How Salty Is Your Undercarriage?
May 5, 2018 11:05 AM   Subscribe

That's not a euphemism. Does vehicle undercoating really protect from corrosion? Salty details inside.

I live in Vermont, which is one of those places where they salt the roads during the endless months of winter. I also live on a dirt road, which probably combines with the salt and snow to cake the underside of my car with a layer of corrosive muck that stays there from November until May.

After nine years, my my last car was still running great--and even looked pretty good--when I discovered that the undercarriage was basically rotting away. It was a sad end to a car that I loved: I couldn't even resell it.

Now that winter is over, I wonder about protecting my (fairly) new car from future winters. Is it even possible without moving South? There are a lot of companies around here who will undercoat your car with oil or lanolin or who knows what, and this stuff is supposed to prevent corrosion. But does it really? Or would I just be throwing my money away?
posted by baseballpajamas to Travel & Transportation (4 answers total) 3 users marked this as a favorite
Even if it does initially provide some protection, any coating will get damaged over time and allow water, salt, grime, and whatever else to do its work. The only real defense is very frequent washing, especially when you've been driving on wet and salty roads collecting spray.

This is most easily done at an automatic car wash with an undercarriage spray, but you can get attachments for a garden hose if you have a spigot that is usable in winter if the car wash is too expensive.

That said, few cars are worth all that much after 9-10 years, and you shouldn't feel bad about scrapping it. It's highly likely that many of its parts live on as an inexpensive source of repair parts for other people's cars and the steel is all but guaranteed to eventually be recycled, so it's not as if it went completely to waste. The point being that it's not the end of the world if you either can't keep up the routine or try and end up failing to prevent serious corrosion, so don't beat yourself up in any event.
posted by wierdo at 11:58 AM on May 5, 2018 [1 favorite]

Best answer: Here in Nova Scotia, everyone I know is obsessed with yearly undercoatings. All I know is that everyone around here thinks it works.
posted by MangoNews at 12:08 PM on May 5, 2018 [1 favorite]

A one time dealer applied undercoating? Probably not worth it. Regular cleaning and undercoating with an oil based product will definitely make a difference, as will monitoring the state of the car's undercarriage and addressing rusty spots before they get out of hand.
posted by Larry David Syndrome at 1:51 PM on May 5, 2018

Best answer: Here's a link to a study (pdf ) performed by the Canadian military:

Review of Corrosion Control Programs and Research Activities for Army Vehicles

They tested various Corrosion preventive compounds (CPC) which are "fluids that are used in a temporary capacity to provide an extra layer of protection for equipment where the original protective coating has degraded. They can be classified by the type of film they develop after curing, i.e., hard, waxy or oily." page 9

" In a benign environment, all the CPCs tested performed equally well.
In more severe environments, the choice of CPC is important. Of the CPCs tested, Corrosion Free, Formula 3000 showed the most corrosion inhibition."

They tested these compounds:

WD-40 ; Corrosion Free Formula 3000 ; ACF-50 Lear Chemical Research Corp; LPS-2 LPS Laboratories; Krown T-40 Krown Body Maintenance; Rustcheck Dripless Rust Check Corp. ;Corrosion Block Lear Chemical Research Corp.;,Boeshield T-9 PMS Products Inc.;Rustcheck, Red Rust Check Corp
posted by yyz at 7:28 AM on May 6, 2018 [1 favorite]

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