Undercoating for rust protection?

[mahu]

So my brother in law who restores old Mustangs reacted all shocked when I told him about the van conversion and he found out that I hadn't put an undercoat underneath the NV.

I didn't even know that was a thing...

He is trying to convince me that I need to undercoat the van asap to prevent rust especially since they salt the roads here in Tahoe.

Any thoughts? Is it really necessary?

Being from Germany where roads are salted and wet for many many months and the climate is quite wet I haven't heard of anyone with a new(er) car having rust issues. I thought that was a thing of the past.

So, is he just being paranoid based on his work with old rusted-through Mustangs or should I consider an undercoat? Thanks!

[andy_george]

Just like motor oil, everyone has their own theories. Here's mine: rust most definetly does still happen, especially in northern states like my home state of Michigan. They spread the sh*t so thick in the winter it turns the road white. Spraying down the sheet metal and underbody as much as possible, along with waxing, seems to help a lot. Have I ever seen a car with undercoating defy nature and physics and not rust at nearly the same rate as non-undercoated...? Nope.

 

It may be different where you are, but my opinion is that the only way to prevent serious rust is washing and washing more.

[wollip]

I agree with andy__george. Keeping it clean goes a long way.

Having said that, I did apply an undercoating type product to my rear tire wells for two reasons. First, I wanted the tire wells to be black - purely my preference for how it should look. Second, I wanted to cut down on heat transfer from that area into the cargo space.

A product called MetalShield (from metalshield.com) worked very well. I applied it with a cheap disposable brush and recoat once a year for appearance sake.

[andy_george]

I did the same thing to the rear wheel wells. I think they look better in black. Although I went the lazier route and just used rattle-can black, and I'm quite surprised how well it's stayed on....

[Chris_CommercialManager]

My opinion, but undercoatings on the chassis are snake oil.  In my mind, the manufacturer (who keep in mind has an army of robots, engineers, and a mountain of research dollars) can and does provide the most technologically advanced corrosion barrier for their own product.  

 

Your brother in law you referenced with old mustangs is working with a different animal.  Technology now available was not present when those vehicles were produced.  I'm sure there are things that could be done but I'd hope he doesn't drive a nice restored mustang on salty roads :(

 

You WILL get rust in any modern car if you are in a salt area,even with steps to stave it off, it's not a matter of if, but when.  I worked for sprinter in Chicago.  I've seen every car known to man on a lift at various ages.  Now down here in the south we know a northern car immediately when we see one.  

[Chris_CommercialManager]

To add to that, we know a coastal car here in Charlotte when we see one too.  If care is not take at the beach through regular rinsing the result can be much the same as the northern cars with salt on the road.

[SigScirocco]

My two cents from Cochrane Alberta.....

Just had my new NV 2500 undercoated at shop not attached to the dealer.  $420 CND with a seven year warranty with free yearly touch up's.  The noise on gravel roads was greatly reduced and have to say the black looks better in the wheel wells.  I will still get under the vehicle and apply a oil/wax to areas not undercoated to further protect from the elements and associated corrosion. 

From articles I read, the Canadian military concluded the oil/wax method was the preferred corrosion prevention method.  I applied the undercoating for the noise reduction first, corrosion protection second.