Why is the snow under my car greenish and yellow in color? Do I have a coolant leak?

During the recent blizzard of 2022 many of us that were not fortunate, to have garage parking found out what it is like to have your vehicle be completely buried in snow and then have the back breaking work of shoveling it out.

After all the hard-work and you’ve finally freed your vehicle you may have noticed a yellowish-green stain underneath that's found along the exhaust system. You probably thought to yourself "oh great, now I have to deal with a coolant leak or car issues". Not to worry, in most instances it's just science to blame for this natural phenomenon so take a deep breath, and read on if you're curious.

Most exhaust systems found on modern cars are comprised of iron alloy and galvanized steel. The heat shields under your vehicle are also mostly comprised of the same galvanized steel, which happens to contain Zinc. When Zinc is heated and in the presence of iron and a "certain catalyst", a chemical reaction occurs which creates yellow zinc oxide crystals. That catalyst just happens to be salt water.

So there you have it. There is a chemical reaction between the metals in your exhaust system and the salt & snow from the road creating yellow zinc oxide crystals left behind in the snow.

If you have any other questions or concerns about your vehicle please contact our service department for assistance at 716-923-2100.

-Drive Safe!