I live in the rust belt of Cleveland Ohio. Ive seen my share of trucks toasted after only a few years. My former truck which I still have is a 06 2500HD. By now the doors, rockers, tailgate, fenders and cab corners would be gone right now but when I got it at 50K it was babied and I have sprayed the lower doors until the oil seeps out of all drain holes every winter along with a smear of Grease along the pinch welds , same with tailgate , rockers and everywhere else. I am happy to say theres not a smidge of rust on it with 130K. Ive bore scoped the rockers though access holes and its 98% clean in there like the day it was bought. Is it nessesary to do it the same way with the aluminum body. Ive search post on here and also google but I am getting mixed reviews online. I saved up for the past few years for this truck and don't have the luxury of trading in every 3-5 years. This will be with me for 15+ Thoughts? Ive though about getting the bottom oil sprayed also.

 

I dunno about the aluminum but this brings back memories of the 70s and 80s when trucks rusted so bad and some commercial fisherman here would dump oil right in the bed, then let it ooze down to coat everything. Then they would put a sheet of plywood in the bed to cover up the oil. Messy, but effective. BTW there was no Linex back then LOL.

 

 

 

 

Back in the early 80's I would take my drain oil and put it in a sprayer and spray the undercarriage of my 68 F100. Never a spot of rust ever.

 

I'm not really tempted to mess with this on an aluminum bodied truck. But if I were concerned about undercarriage components I'd probably try Fluid Film. Made from lanolin, it wouldn't be toxic to anything where it drips off of the truck.

 

+1 for Fluid Film. Used on my 2015 F350 while living in Michigan. Looked factory fresh when I traded for F450 two years later.

 

I keep a gallon can of it on hand for painting the underside of my riding mower decks and my 6 foot snowblower chute. Pretty good stuff.

 

 

It can be sprayed but it's at a high pressure. https://www.fluid-film.com/spraying-fluid-film/

​​​​​​https://www.fluid-film.com/automotive-applications/

It can be thinned with vegetable oil. Here's a FAQ:
​​​​​​https://www.fluid-film.com/frequently-asked-questions/

 

Fluid Film is great and easy DIY. For example, I have used it on my TT with really nice results...especially effective around the strong arms supports that get exposed to so much road grit, grime, water, salt, etc.

 

I ordered the Fluid Film 'kit'. It came with a nice sprayer w/quart jar I used with my small Dewalt air compressor, some different nozzles for getting into tight places and drain holes, a gallon of Fluid Film, a spray can of Fluid Film, and some other stuff....can't remember, some Fluid Film swag. Was very easy to apply using their sprayer. First application takes the longest just because you want to hit everything at least once. Touch-ups after that were quick and easy. Truck is tall enough I didn't even jack it up....just slid underneath and sprayed.

 

Not sure why they say such high pressure is used. The sprayer they sell is set up to spray the Fluid Film straight out of the can. Instructions advised using simple air compressor. My DeWalt could go to 120-150 PSI I think??? but it actually sprayed best at much lower pressure. I seem to recall it was around 70-90 PSI worked best. It isn't necessary to thin it. I sprayed it straight out of the can. One gallon lasted couple applications for me.

 

I ordered from here https://www.kellsportproducts.com/