rust proofing the underside of new vehicle

[DrPhantom]

Sorry everyone but I just ordered a Wrangler Sahara Unlimited. I wish F5 would have come up with a PU truck, but I couldn't wait. Cobra and Daytona are ruled out for me -- I have back problems (old fart) and need a high seat front, 90 degree knee bend, vertical torso, and lumbar pillow.

I usually drive vehicles into the ground so I want to get 15+ years out of this Jeep. All the body panels are galvanized, plus they are replaceable, so I'm not worried about them. The frame may be galvanized but I think it will turn to rot in less than 10 years -- not acceptable. I have no garage and I have to park it in the street salt all winter.

What are your ideas about rust proofing?

FWIW: My plan is to paint all the underside (except moving parts) with POR15, then to spray the body panel undersides with 3M rubberized coating -- no 3M on the frame though. My thoughts were that the POR15 would penetrate into all the joints and seams while the 3M Stuff would enhance rust protection as well as provide sound deadening.

I'd appreciate your reactions or suggestions about what you have done with iron frame parts...

Tom

[AC Bill]

POR 15 is a great paint, as long as it's not exposed to UV light. It's tougher than nails when applied properly, and should last for many years. It is also tricky to work with, as any accidental spills, or over-spray, is extremely hard to remove. This includes your skin. I've only ever brushed it on, and simply disposed of the brush's etc., afterward, so I am not sure what you would do, in trying to clean up spray equipment. Your gun , and nozzles might never be the same again..lol Likewise with your hoist, jack-stands, jack, garage floor, etc, etc.
Some fellows recommend using truck bed liner, rather than undercoat spray, as it is extremely resilient. I wonder though if either is a good think on a daily driver, that is out in the weather all the time. I had a newer vehicle completely undercoated with a tar based undercoat. It lasted, and did act well as a sound deadener. But...after about 10 years it dried out, and began to crack. Those cracks allowed water to work it's way in, and trap it between the undercoating, and a frame member. The frame rusted extremely badly within just a few years..
Since then, I have only used Wax-oil, or Tremclad rust paint, on the underside of my daily drivers. I have a truck that is 27 years old, exposed to winters here in British Columbia, and other than a couple spots of body rust above the rear wheel wells, it is in very good shape still, with a solid frame, that has nothing more than surface rust.

I don't know what the manufactures warranty is for Jeep, but perhaps you should be concerned that any coatings that you apply yourself, may somehow void the rust warranty. You might want to check up on that first.

[DrPhantom]

Thanks, Bill, for the advice.

I have heard similar stories about tar-based and other "thicker" products losing adhesion and providing pockets for moisture to remain in prolonged contact with the metal they were supposed to protect.

The POR15 UV sensitivity is a problem, maybe I should use Rust-Oleum or Magnet Paint on the frame. I'm not 'sold' on either, tho, as Rust-Oleum might be wimpy and the Magnet Paint dries glossy.

Good suggestion, too, about the warranty -- I'll have to check.

Tom