Underbody rust

**itzharrison** · 03-28-2014

anyone know how to treat underbody rust? I have a 2002 grand am gt from Michigan it has low miles but quite a bit of underbody rust. I tried a spray on rust thing it was supposed to turn the rust black so its not so noticeable and prevent rust and it didnt even turn black.... I'm getting ready to sell the car so I really just don't want it to be noticeable.. Please no stupid "Grand Am" jokes and please no trollling by saying black spray paint. what do you guys recommend for less then $50

**Russosaur** · 03-28-2014

I used rust converter and it didnt really turn black. Like yours. Honestly unless its rusting out I wouldn't bother. Its Michigan is an excuse if they point it out. Otherwise some sand paper and black spray paint would work. The only sure fireway to fix it is sand down to metal, primer, paint.

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**itzharrison** · 03-28-2014

yeah man its rusting out, I poked a couple 2 inch holes in the back bumper and the rear axle looks awful.. It's too far gone to save, just looking to hide. Would undercoating turn black? that would work for a year

**Russosaur** · 03-28-2014

If its too far gone, black spray paint. Would cover it up for what you want to see. What do you mean undercoating? Like having someone spray something under the whole car?

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**itzharrison** · 03-28-2014

midwest weathers are really that bad. In Illinois we get a inch of snow followed by 2 inches of salt just in case. especially Michigan where they use spray salt, ruins cars! I wouldn't be surprised if they did it on purpose when the Michigan GM was still going.

**Russosaur** · 03-28-2014

For being an Ohio car, mine has the rockers with zero rust at 140k. With rust that ate through the RR fender some because then PO did a crap job fixing with which isolated it cauing it to rust through fast. My trick is lots of underbody car washes durring winter when it gets above freezing. Another reason I was to move south when I can.

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**itzharrison** · 03-28-2014

yeah too late for that. Like I said I was poking holes through the rear bumper bar.

**Russosaur** · 03-28-2014

Black paint what you can but it wont help the rust and might make it worse in the longrun.

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**itzharrison** · 03-28-2014

that'd be kinda ****ty to whoever buys it. Does a undercoat come out black? maybe that would work? I've never undercoated a car.

**Russosaur** · 03-28-2014

Never heard of it or tried it personally.

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**itzharrison** · 03-28-2014

Dealerships offer undercoating on new cars for a couple hundred dollars. It protects the underbody from salt instead of salt getting bare metal. It's mainly a Wax that lasts a year or two for the underbody. Just protects bare metal its recommended if you live in the midwest with a new car.

**Russosaur** · 03-28-2014

Problem I see is it gonna seal up the rust and not gonna help much. Iv heard those coating crack, let salt in then it has no place to go and eats through metal like a fat kid in a candy shop.

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**idrivejunk** · 03-29-2014

If you can jab a hole in the rear bumper bar ... I'd forget about truly trying to kill rust or preserve whats left, and just make the bad spots look better with a few shots of aerosol "rubberized undercoating". Tons of different brands are out there, any can of it that sprays good will work. It has a nice textured dull black appearance that you can fade out or lay on heavy. Good at hiding things but its a bodyman's nightmare if anybody ever goes in to fix it right. Just messy to strip off later. But in the meantime, it will provide a small amount of protection for the crusty metal. It is water based so black spray paint first ain't a bad idea, but the textured undercoating will get you the quick fresh look you need for marketing the car. Try to keep it off the plastic splash shields, maybe mask a little because those look worse with undercoat on them.