What Chicago road salt actually does to your car's paint

Salt is a chemical problem, not a dirt problem

Road salt and liquid brine lower the freezing point of water on the road — and accelerate corrosion on your car. Salt doesn't just sit on the surface. It works into stone chips, door edges, wheel arches and any spot where the clear coat is already compromised, and it keeps reacting with the metal underneath long after the roads dry.

That's why a car can look fine in January and show bubbling paint by May. The damage happened in winter; you just couldn't see it yet.

The spots that go first

On most cars we see the same pattern: the leading edge of the hood and roof from stone chips, rocker panels and lower doors from road spray, wheel arches, and the lip around the trunk and fuel door. Aluminum body panels don't rust the way steel does, but the paint still lifts and corrodes around chips.

A chip the size of a pencil tip is enough. Once bare metal is exposed, salt and moisture do the rest.

What you can do yourself

Wash the car — including the underbody — every couple of weeks through winter, and after any stretch of heavy salting. Touch up stone chips before they see a winter, not after. A wax or sealant before November gives the clear coat a sacrificial layer.

If you can already see bubbling, flaking or a brown stain creeping from a chip, washing won't stop it. That's corrosion under the paint film, and it needs to be ground out and refinished before it spreads.

When to bring it in

Small rust spots are some of the cheapest body repairs there are — caught early, it's a localized refinishing job. Left for two or three winters, the same spot becomes a panel repair. If you're not sure which one you're looking at, send us a photo and we'll tell you straight.