“Never buy a car from the north!”, words my Ohio born and raised father always told me. Though, as a California born and raised native myself, I didn’t really know what the difference was. I knew he was talked about something to do with the snow, but why would a car that’s been snowed on be any different than a car that’s been rained on? Of course, as someone who lives in an area of the country that gets snow now, I understand it — it wasn’t anything to do with the snow itself, it’s the treatment of the roads in reaction to it that ruins a car. But there’s a new twist to this problem most gearheads were already aware of.

Back in those days, the problem was rock salt/road salt, but don’t worry, most state Department of Transportation offices have a found a way to make methods of clearing the road much worse on your car. In recent winter seasons, the local DOTs have begun spraying hundreds of thousands of gallons of a salt solution, known as brine, to prevent salt from sticking to roads. The benefit to using brine over rock salt is that it will get into places that crystallized salt cannot — it’s also cheaper and more effective. So maybe it’s better for you as a driver, but not as a car owner, and certainly not if you’re a gearhead or collector.

Brine is way more damaging to your car because part of the salt solution is magnesium chloride, a corrosive demon! While rock salt remains in crystal form until humidity is at 70%, magnesium chloride dissolves at 20-30% humidity — meaning, it’s pretty much going to be drawing moisture from the air, constantly. Not only does it remain in a state of salty moisture, it sneaks into places rock salt wouldn’t normally be able to reach, so small areas of the frame, floor pan, exhaust…the list goes on, are all at risk when it comes to brine.

The older your car is, the more at risk it will be with brine since there are far more metal components on them than new cars — which is really bad news for hot rodders, but even modern gearheads should worry since there’s metal on your car somewhere, and brine will find it.

If you can’t avoid it, wash it off as soon as possible, and avoid parking garages/your garage by any means necessary until it is washed off — remember that it takes very little humidity to keep it wet, and even a 45 degree parking garage will put it in range. There’s also various undercoating, fluid film, and cavity wax options out there to fill in small crevasses, which is probably a good investment if you live in areas where snow and ice are frequent elements of your landscape.

So in conclusion, rock salt was damaging, but brine will make you long for the days of rock salt on winter roads. Brine will attack your car because it draws moisture from low humidity, and has an added magnesium chloride to make matters worse, so you need to wash it off right away. I’ll never turn my nose up at people who put their street cars up for the winter again, seems like a pretty good idea with brine being used as the primary pavement treatment when it snows.