Advice for protecting a southern truck from road salt

If you absolutely have to drive it in the winter, the best I've seen is the dripless oil undercoating they use in Canada. I'm sure it is used in some states, just don't know which ones, and certainly not Michigan.

Just cover it in hot tar,maybe undercoat everything?

Never gonna wash it?

Wow, lots of smart #%#$ answers I never thought about. Thanks for those who gave a genuine response. I'm not so much worried about the underside, I won't be driving it daily and I will wash it more than regularly. I was really looking to protect the lower 1/4 of the truck on the exterior with some kind of clear chip guard and though maybe someone could recommend what they've used.

Up here In Toronto we have a good product called Krown rust control,
it is a thin oil that they spray all thru the inside of all the panels and the underside.
I have used it on my 89 Dodge van and it still has no rust.
The good thing about the thin oil is that it creeps into all the seams of the metal where water likes to get into and never dry and starts to rust.
The oil will prevent that from happening.
If the oil or rust treatment is too thick it will only create a bridge and in the cold will get harder and water can sit under it and cause rust.
I have seen that many times on cars where it rusted under the waxy spray stuff.
Try to find out if they have any dealers in the states or look for thin over thick.
Don't use old motor oil.

http://www.krown.com/#default

You could always spray on rocker guard on the bottom 12" of the truck. It's that textured spray on stuff, usually dries to a semi-gloss black. I've seen it used lots on vehicles that are chipped up on the bottom or vehicles that someone did some bondo rust repair and didn't want to paint the whole vehicle. Very durable stuff.

Aside from factory undercoating, Rustcheck works, and you can do it yourself. Be sure everything is bone dry when you apply it.

I lived in chicago many years before moving south and found that frequent washing at car washes will hasten the rust problem. Most car washes merely filter the water used due to the expense of high water bills so the salt from every other car gets into the water you are spraying on your vehicle. Also, the salt water brew you are spraying will get into every space of your vehicle that normal driving would not such as inside doors, under the hood ect. Very few car wash locations use fresh water but they do exist. They advertise the fact that they use only fresh water and they are very expensive by comparison. To prevent rust you would need to follow the advice given about the oil treatments and stay away from regular car wash facilities. Sorry to say, the road salt will still cause you problems but you can slow down the process.

Here in upstate NY the oil treatment is called Rust Stop and it works. I have used it on pre-owned vehicles with great success.

There is only one guarantee. If you drive it, it will rot out. If you park it in the same garage as you park your daily vehicle, it will rot out.

Fix any chipped paint areas, making sure there is no bare nor primered metal exposed.

Interesting info regarding car washes above. Even if the car wash uses clean water (which is good), if the temp gets below freezing and there's water in places you don't want it (panel seams, inside doors, etc.), it'll freeze and expand, exposing fresh metal. This is usually how you get rusting from the inside out, especially on door bottoms and around wheel well arches- paint rarely ever gets applied there when the car is painted at the factory, so it's already a weak spot. If you do wash it in very cold weather, dry it as best you can, and if you have a garage to park it in, do it...even if it's not heated.

My '90 Astro's body has held up very well after driving through three WI winters so far. Native WA state van 'til '04, it was 99% rust free, and despite some roof rust starting, it is still in great shape. I'll be honest, I don't wash it in winter unless we get a 40*+ day on a weekend when it can dry in the sun, but I take care of any chips and make sure there's no bare metal exposed.

Remember, it's not the salt that causes rust, but rather bare metal and water in the presence of oxygen. Does salt accelerate areas that have started to rust? Heck yeah it does, but the freeze/thaw cycles in winter are the real enemy.