ReaperHWK:
What you are doing to prevent rust from forming on your truck is a good idea by washing down the areas that are rust-prone, like fender seams and at the bottom of wheel wells, where snow and ice (and the salt within it it) collects and stays there for weeks on-end during the winter..
There's a great deal of debate on the effects of salt on clear coat. What you need to realize is that it's not the salt, per se, that cause the rust; it's the mild acids that form when salt and water combine to form ionically that REALLY affect iron (steel) and cause it to rust. I don't want to go into technical detail , nor make this a chemistry lecture. The question is, is it strong enough to etch and eat away at clear coat. If it's left to sit there long enough, yes it will. But how long is long enough?
Clear coats are more affected by man-made environment fallout and natural contaminants, such as bird droppings, bug splatter from road kill, and tree sap. THe natural fallouts cause etching in spots that no one like to see. The man-made fallout can etch the clear-coat, especially after it rains and concentrates the pollutants on areas of the vehicle as it dries. So when you try to remove the etching to have a good-looking vehicle, this self-induced polishing, whether it's by wet sanding or machine polishing with abrasives to remove this etching, is of a far greater detriment to the clear-car that the effects of salt because you are physically removing the clear-coat, allbeit by microns (thousandths, 0.001 inch) at a time. Most of the "problems" associated with the effects of salt on paint finishes are because of unattented breaks in the paint, IE Paint chips, that are inevitable from every-day driving of a vehicle.
Most vehicle owners put a sealant/wax on their vehicle for two purposes: 1) to make the paint surface look reflective in a mirror-like gloss, and 2) to protect the paint (clear-coat) from environmental contaminants. Some do a better job at both, like Collinite 845, which is what I use because it providses the best combination of both of these purposes. That being said, no sealant/wax will protect the surface from all contamination, and yes, all sealants/waxes do wear away, depending on the environmental conditions of where you live.
In essense, your truck won't fall apart so soon as those who do not take care of their vehicle like you are doing. BUT, if you drive it long enough through-out the winter years in places where road salt is constantly used to remove snow and ice, it will succum to the invitable rust we all loath. As stated, what you are doing is prolonging the years of driving you will get from your vehicle before it gets really bad.
While we are on this subject of rust, here's another helpful hint you may (or may not) use: Some owner's spray WD-40 along the lower rocker panels and wheel well seams to help prevent rust from forming during the winter months. Does it help?? I don't do this because I think it eats way at the wax/sealant I use, but you can make your own conclusions if you choose to do so.
