How Salt Melts Ice
What salt does is it pushes water molecules apart from each other. Ice can't form when its molecules are being pushed apart. This lowers the freezing point of the water that forms the ice.
This is the same reason freshwater freezes faster than saltwater does. Fresh water's freezing point is 32 degrees Fahrenheit. Seawater freezes at 28.4 degrees Fahrenheit. And road salt introduces a lot more salt than that.
Road departments will add more salt depending on the weather. Seawater is only 3.5% salt. Road departments use 10% salt solutions that freeze at 20 degrees F, or 20-percent solutions that freeze at 2 degrees F. In other words, the lower the temperature goes, the more salt is used.
How Road Salt Forms Rust
The bad news for your vehicle is that salt also forms rust. The lower the temperature goes, and the more ice that's on the road, the more salt your road departments use. The more salt they use, the worse the rust on the underside of your vehicle becomes.
Road salt creates iron oxide when it comes into contact with water and oxygen. Needless to say, there's plenty of both when it's melting ice into water on the road. It's impossible to avoid this. If there were a better solution that was cost-effective, it would be used instead.
Iron oxide speeds up the development of rust. When this mix gets stuck in your vehicle's undercarriage, it can spread rust very quickly. It's incredibly important to have that undercarriage cleaned reliably. The most easily damaged parts are your muffler, exhaust system, hydraulic brakes, coil springs, and subframe. When rust forms on your brake system, this puts your vehicle in danger.
Steps to Avoid Rust on Your Car
Here's what to do to avoid rust build-up in the first place:
- Give the salting trucks space. Driving directly behind a salting truck means that you're picking up the most salt from the road.
- Avoid puddles. Sometimes you can't help it. You don't want to cause an accident trying to avoid a puddle. Yet if you have the opportunity to change lanes, it's a good idea to let that puddle be. It can hold a very high concentration of salt.
- Pre-treat. Collision shops often offer an oil solution used to pretreat your vehicle's undercarriage. It repels salt and water so it's much less likely to get stuck to the underside of your car.
- Wash your vehicle. Get the salt off your car after a snowstorm or freezing temperatures bring out the salt trucks. There are a number of ways to do this, from a drive-through car wash to getting someone with experience to power wash the underside of your vehicle.
- Get your car inspected. It's a good idea to have your car inspected before the worst winter weather hits. Your mechanic can identify any risks or needs. This doesn't just help with rust-proofing; it also ensures you don't end up broken down on the road in the middle of a snowstorm.
- Wax your car. This won't help your undercarriage, but it will protect all the surfaces you can wax. Salt can cling to anything and cause rust, so this will help protect the rest of your car.
- Get dents repaired. Dents won't cause rust, but in the right places, they can allow meltwater in areas that should otherwise be sealed. A dent near the window can create a gap in the seal that keeps water out there, for instance. That kind of gap can lead to rust inside your car, though it's more likely to grow mold or mildew. It's a good idea to get these dents looked at and repaired before winter. Snow sits on top of your car and melts when the sun is out, so you don't want unseen rivers taking advantage of these easy-to-fix dents.
Get Your Vehicle through Winter in Good Shape
Address warning lights as they come on. It's not a good idea to let one sit there throughout winter. This is asking to end up stranded in bad conditions, and you don't want that.
You don't have to make a ton of trips to cover all of these things. You can get many of these services at an auto repair shop.
You'll want to make sure your car's in top shape come spring. Winter is the harshest season on everyone's car, in so many ways. Get through it with your car in good condition, and you can wash that salt off and have confidence in your ride throughout the rest of the year. Contact us for dent and ding repair.