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  1. #1

    Question Question on undercoating

    So a question for those of you that live in the rust belts and harsh winters with salted roads.

    My Cousin has 2009 Chevy 2500HD LTZ 4x4 diesel. He will be spending 2 winters in Wisconsin (in the Navy and they are building on of the new LCS ships there). He is wondering if/how important is undercoating for protecting his truck. Is it worth it? Easy to do (DIY or pay someone to do it)? Pros, cons etc. Any feedback would be great.

    2004 Silverado 2500 Crew Cab 4x4, AMSOIL EA air filter, Granatelli MAF sensor, Throttle body spacer, Magnaflow exhaust (true dual to 2 in 1 out muffler), 6" ProComp lift (add a leaf and 5" superlift rear block), Bilstein shocks, 35's (Cooper Disoverer ST) and 4.10 gears, Rhino Liner, EGRUSA fender Flares and widow visors, extended stainless steel brake lines, firestone airbags w/onboard air compressor, Pioneer Avic X940BT navigation, Accel backup camera.
    1960 Land Rover Series II 88
    2001 Pontiac Sunfire
    2013 Toyota Avalon Limited (Wife's Car)
    NRA Life Member

  2. #2


    I have lived in Michigan my entire life, so I know a little something about rust. As far as under coating goes, I know people that swear by it, then I know others that hate it. If you look at used cars for sale you see some with ziebart under coating that are nearly rust free. Then you see others with it that are total rust buckets. The problem I have with it is that many times you can remove it if you get too close to it with a pressure washer. One theory that the opponents of under coating use is that when a rock or something scratches the under coating it allows for water to get behind it and then the water is held against the metal and does not dry, causing rust. I have seen tons of brake lines rust out on GM trucks. It happens up in the frame rail on the drivers side, Water just sits on them. Personally, I would do it myself with one of the Eastwood product line. Basically you buy a bunch of cans of the stuff and spray down your entire under carriage before winter starts. The advantage of this over lets say Ziebart is that you can spray almost everything (control arms, brake lines, bolts, nuts, axle, frame, underbody) except your brake rotors. while Ziebart basically does the body underside and the frame. Then the next winter you spray it on again. I wish the po of my truck had done this, it would make working on it much easier.

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors,
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  3. #3


    Thanks, I will look into that.

  4. #4


    I would do it yourself. I picked up a few cans from Advanced Auto. Its was on sale so I got a few more cans and doing my car as well. A plus on doing it yourself is you know exactly what you covered.
    -K&N Air Filter

  5. #5
    Jr. Engineer poncho62's Avatar
    Join Date
    Sep 2013
    Hanover, Ont, Canada


    My truck is 16 years old (1997)..It was undercoated regularly since new, so I understand.....It has little to no rust. There are a couple of minor spots in the bed that have a bit of surface rust, was not undercoated there. I just had it undercoated again...cost me $100

    Only disadvantage to it is that the undercoating makes it messy when you need to do some work on it

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  6. #6

    Join Date
    Sep 2010
    everett, massachusetts


    I have used a undercoating called rusfre 1013. comes in a gallon can. this is firberglass re-inforced black solvent based coating. once this goes on it sticks quite well. I have used this since 1998 . you thin it with mineral spirits to get the desired product viscosity to brush on or spray on.

    I have tested this by just scraping of rusted metal then with this product applied it stops the rust.

    If you screw up the product comes off easy with mineral spirits. I did my wheel wells 13 years ago still no rust. touch up every 5 years when you put on 2 coats . best wait a few days between applying.

    this is the product,,,

    I go it at my local body shop paint supply store.

    I have to say that the GM black coating used is no good at all. after a few years this product holds water and corrosion ..this begins when the warranty ends. I scraped of this gunk when I first saw this where it is used on the frame. then I applied the rusfre. all the rust is gone.

    I did have a cross member tube rot out from the inside out because of the GM coating held the corrosives inside the tube above the fuel tank. the only rust on the vehicle. this is because I could not get that GM crap out from inside this tube. when the new tube was welded into place I made up a round brush head and coated the inside of this tube .....still looks new..the other area is the rear shackles.. best coat those where they bolt on to the frame and also the entire rear inside portion of the rear bumper..

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