Originally Posted By: supton
That's not a fix, that's a preventative measure. Best done prior to the damage. Also, depending upon usage you may have to do more like twice a year, not every other year.
Takes like two cans just to do the frame on my truck, toss in a couple more to get sheetmetal and whatnot. Don't forget to get exposed bolts and hose clamps and wiring. Best I can tell, soaking everything short of rotors and exhaust is the way to go.
I was specifically talking about spraying fluid film inside all of the cavities of your vehicle. Since there is no real way for large amounds of water, salt or contaminates to get inside the cavities, a heavy application of fluid film once every few years should prevent any problems. Even in non corrosion regions like down south, I still think this would be a good idea.
As far as the undercarriage goes, I have been experimenting with undercoating recently. Those treatments need yearly application and but I do feel they are worth the price and trouble if you do them yourself. If you are going to pay someone.... probably too expensive. I say either do it yourself or just pressure wash your undercarriage weekly if you live in a corrosive region. Fix any scratches in the paint, wash your car frequently and wax frequently for the best results. It's no secret, take care of your car and it wont rot out.
I wasn't going to say this for fear of a flame war but I think I have to. One reason you see American vehicles with rust more so than imports, I think is because of the type of owners that American vehicles have. People who drive Chevrolet trucks especially, tend to do less cleaning and maintenance than drivers of imports, especially the people who buy imports new. Also, trucks of any brand tend to be used hard, offroaded, ripped through the snow and just generally beat on more so that cars and SUVs, worsening any rust issues. This issue of certain cars have certain "types" of owners is certainly a valid one. Here is the wall street journal confirming something else I have noticed, BMW drivers tend to be rude, pushy and impatient type drivers. I have been saying that for a while and now it seems a fairly reputable source has data that agrees with me on it.
http://blogs.marketwatch.com/thetell/2013/08/13/bmw-drivers-really-are-jerks-studies-find/