06quad

With winter around the corner, what do you guys think about undercoating the underside of a truck? I have heard arguments that go both ways. Some say it is good to keep salt off of the sheetmetal and rust a bay in the winter. Others say that it catches salt and water and holds it there. I will wash my truck top and bottom at the carwash as often as the weather is warm enough to let me. I want to do whatever is best to keep my truck in good shape for years to come. What do you think?

pet05

I would make sure if you do rubberize the bottom that ALL DRAIN HOLES remain open. I don't think it would hurt to rubberize the bottom. I don't see how it would hold the salt.

I live in Arizona and even though it DOES SNOW in northern Arizona they DO NOT use salt. They use a gravel/ash mix. I used to live in Chicago and they salted ALL WINTER. The cars would rust within a few years, especially the bottom of the vehicle. I hated it. I had a 89 Pontiac that the doors were rotted after 7 years. The salt mixture got inside the door panel and it is VERY difficult to get it out.

I heard that they do NOT use salt in Colorado either, is this true?

Syndicate

Use LineX its a better coating.

Mexstan

ANY thick material, rubberizing etc under a vehicle is bad news. As it is impossible to make sure that it has completely bonded to all the surfaces, over time it is guaranteed to delamintate and trap corrosive material.
The special 'creeping' oil designed for this purpose is FAR superior, even if it has to be applied annually. The best of all is Krown rust control, http://www.krown.com/ but unfortunately they are only available in Canada. Take a look at their site as to how it is applied.

Turbobob

Another product is ACF-50. It has been used in the aviation industry for years. It kills corrosion on contact and prevents further corrosion. Google ACF-50 and see what you can find. If I remember correctly, you could buy it in spray cans or in 5 gallon containers and spray it with a solvent sprayer. My 2000 Dodge saw 6 winters(They salt heavily in Utah)and it had NO rust when I sold it last month. I just hit the quarter car wash after each storm and blast off the bottom side.

Mexstan

ACF-50 is a great product as it works really well. However it will only work where it can reach or make contact with. The only sure way to make sure that products like this reach the hidden areas is to drill holes and spray it in.

kawi600

A lot of these rust convertors just contain phosphoric acid and sometimes zinc. It etches the metal and leaves a layer of material that doesnt allow the rust to start. I used spray paraffin for awhile and found that not only did it come off too soon, but it made doing bodywork later on a real pain in the butt.
I bought a gallon of that metal-ready stuff from POR and its the usual phosphoric acid and zinc stuff, but even by itself it seems to do a good job with the rust. I use it on bare metal before I prime and paint too
One thing you might want to do is drill holes in the bottom of the doors and rockers right at the very lowest point where water will gather, and spray a bunch of the metal-ready inside so it coats the insides and keeps it from rusting.
Another thing youll want to do is drill drain holes in the front cab mounts where it comes down to meet the frame. They collect amazing amounts of sand and the water sits inside and rusts it out. I blew mine out with compressed air and it was like a sandstorm rolled in.
I think once rust gets a purchase on something via a chip, an unprotected edge, a weld or whatever, it spreads under the paint. any layer over the metal will trap the stuff. Better to have something you can see through so you know when to remove the stuff. Id stay clear of rubberized undercoatings =(

Blast Chamber

When I bought my truck I power washed the undercarriage, let it dry for a day and then went at it with Rustoleum black spray paint. I especially coated the backside of the bed panels as they were easy to access from underneath and by removing the taillights. So far the paint is holding up great with no rust problems whatsoever.

I also think that installing rear wheel well liners helps to keep the winter salt/slush off the chassis.