Many states across the country that experience heavy snow in winter have changed to another type of road salt — magnesium chloride. While it’s very capable of keeping roads safe, it’s ready to promote rust in cars a lot more rapidly than regular rock salt. Here is advice on what you can do to protect your vehicle from magnesium chloride.

Related: What to Do With Your Car When It Snows

The New Road Salt, Magnesium Chloride

In 2015, Ford Motor Company recalled close to a million vehicles, the Fusion and the Lincoln MKZ among them for premature rusting. The majority of the vehicles affected were in the northern portion of the country with heavy exposure to snowfall. In the winter of 2015, Toyota recalled a similar variety of Tacoma trucks affected with a similar rust issue. Roads and bridges throughout the Snow Belt have been reported to possess significant rusting and corrosion damage.

The one common thread in all three examples is this: magnesium chloride, an extremely effective deicing agent sprayed on roads in many nations. While common rock salt was the agent of choice before, it used readily wash off, necessitating repeated sprays. The staying power of magnesium chloride over regular rock salt has made it much more desirable. While it’s very good as a means to keep streets ice-free, however, it’s nothing short of catastrophic for automobile underbodies.

See also: 20 Safe Driving Tips for Winter

What does magnesium chloride do to your car?

If your tires chum up street salt mixed in with snow, a lot of it tends to end up sticking to the underbody. While common salt does adhere and does rust, it tends to remain in undissolved crystal form until environmental humidity reaches an extremely high 70%. This is not common in winter.

Magnesium chloride, however, dissolves at 20% humidity, which is common in winter. It follows that when magnesium chloride gets on your vehicle’s underbody, it turns into liquid acid and coats every surface. Magnesium chloride is far more corrosive than rock salt, as a result.

Frequent advice for the salt problem is simply never to drive directly behind a salting truck and to shell out the $10, or $20 it can take to get your vehicle into a fantastic car wash the day after each heavy snow storm.

Read: 6 Important Fluids in Your Car to Check on a Regular Basis

What if you’ve seen that nothing really happens?

Maybe you know people that don’t take the car wash rule very seriously. They typically wash their vehicles just at the end of winter, and it may have never appeared to make their automobile worse. That said, should you really be concerned about rust and looking for a solution?

The issue with looking at isolated instances is they probably have not had enough time to really experience what magnesium chloride can do. Many states have just recently switched to the material, after all. The other issue is that new cars are inclined to have the ability to resist corrosion for longer, just as they’re newer.

If a buddy who has experienced no troubles drives a brand new automobile, the rust likely only hasn’t had time to reveal. For anybody who drives an older vehicle, however, rust over the years is very likely to have weakened the metal. Magnesium chloride can quicken the procedure.

The reality Is that magnesium chloride turns in acid, and acid does corrode plastic and metal.

Recommended: How to Cut Automotive Gas Costs

How dangerous is magnesium chloride?

Corrosion on automobile parts is harmful. Folks do report collapsed brakes, triggered engine warning lights and broken leaf springs. The older the vehicle, the more rapidly these issues show up. It is important to take actions.

What else can you do?

While carwashes are a fair solution, they are not as effective as they may seem. When streets are sprayed, crews combine salt with water and spray it. Liquid brine can enter every crevice in your vehicle. Car washes are not able to travel that deep inside. Their wash detergents are not able to neutralize additives, either. Few carwashes utilize the low pH detergents needed.

While some bus and truck manufacturers have shifted to expensive stainless steel underbody parts, these are not an option for regular car owners. Rust prevention coatings would be the most reasonable option to go with. Numerous possibilities exist. Some companies provide a thick, tar-based coating. These products work best with new cars that don’t have some rust to start. Others give an effective ceramic application.

You should look for a warranty

Even though a variety of rival underbody protection products are available, only a few sellers are convinced enough of the potency of their products to supply a multiple-year warranty. If you can get this sort of guarantee on a rust prevention product, you should take it, even if you don’t intend on holding on to a brand new car any longer than five years. While the rust which develops in that period likely won’t cause catastrophic failure, it is going to diminish the value of your car when you sell.