Prevent Rusting by Protecting Your Vehicle from Road Salt
If you live in an area with cold, snowy winters, you're probably very familiar with road salt. Applying salt to icy roads is a very common way to melt the ice and keep roads and sidewalks from becoming slippery and dangerous.
However, road salt does have a downside—as you drive over roads that have been salted, your wheels can kick salt up onto the underside of your car. Salt speeds up the electrolytic process of rust, and steel and iron that are exposed to saltwater rust much faster than metal exposed to plain water. While there's not much you can do to avoid salt in the winter, there are still steps you can take to prevent salt from damaging your car and leading to costly repairs.
Wash Your Car Frequently
The longer salt sits on your car, the more damage it will do, so it's important to wash that salt off often. Since much of the salt accumulates on the underside of the car, look for places that advertise undercarriage cleaning.
If you need to wash your car yourself, don't neglect the underside and the wheel wells. It can be difficult to see how dirty these areas are, so spraying them from a hose until the water runs clear is a common technique. But since you won't be able to see whether this water is salty or not, err on the safe side and give it a few minutes past the point of clear water.
Wax & Seal
Waxing your car and sealing the wax will help protect the painted areas of your car from winter damage. Wax doesn't directly fight rust; instead, it keeps your paint in good shape, and the paint itself acts as a barrier that protects the metal underneath.
Since you should be washing your car frequently in the winter, it's important to note that dish soap can cut through and remove car wax. It's best to buy soap that's specifically made for washing cars; however, you can use dish soap as long as you re-wax your car afterwards.
Apply Rust Inhibitor
While ordinary car wax protects painted areas, much of the undercarriage of your car is bare metal. For areas like this, you need to apply a rust inhibitor spray. Petroleum-based rust inhibitor is a good choice for the undercarriage as it will continue to slide over the metal after application, filling in small areas you may miss during application. This also means that it will move back to fill in small spots that are worn away by regular driving.
For more visible parts of the car, petroleum inhibitors may be too slippery. If you have areas of bare metal higher on your car, look for "drying" or bitumen-based inhibitors that will harden completely after application. If you have a way to easily access your undercarriage, this type of inhibitor can be used there as well; however, it's important that you don't miss spots as it will not move to fill in gaps the way petroleum-based inhibitors do.
