Mystery Bumper Damage



We have a brand new 2009 Duramax Silverado with 1460 miles on it. We live in Colorado and the truck is kept in the garage. Colorado uses Magnesium Chloride on the roads in winter. The truck is only driven occasionally but has been on winter roads about 3 times.

After washing the truck recently, the bumpers have alot of red colored spotting that will not wash off nor have chrome cleaners/polishers removed it. Is it the Magnesium Chloride? Is it defective? I have taken pictures but do not see a way to attach them.


I rarely suggest dealers for any reason but I suggest that you take your truck to the dealer. Magnesium chloride is usually white and sometimes clear. You may have driven through something that is staining the chrome.


I assume your vehicle is a light color, white, silver, etc. Most likely this is “rail dust” and is on the bumper and fenders. This can be from a variety of sources but most likely it is from the chopped metal in the brake pads. When the brakes are applied and the pad wears the pad material does not simply disintegrate or fall down. It flies out and since it is hot it melts into the paint and chrome surfaces of the vehicle. It might be buffed out or clay barred out but I would not worry about it since no matter what you do, it will come back.


I Agree With MeanEyedCatz’s Assessment. We’ve Had A Similar Discussion Here Before This One.

Are they tiny “flecks” ? Are they more frequent on lower parts of the vehicle ?

When snow plows plow the roads you can sometimes see the blades sparking and I’ve even noticed a burning metal smell when behind them.

Now that the roads are drying off I can see rusty wide orange stipes going down the roads, left behind by the steel from the plow blades. One theory is that it’s this iron left on the road that gets thrown / splashed up onto cars.

Try a white car. I have white cars and it really shows. It will wax off with enough elbow grease or my small electric random orbit waxer. I’m sure a clay bar would work, too.

Following a few good rains the stuff will be gone from the roads until next winter.

Try a search for “rail dust”.