Salt loves to eat cars, especially when it is used to fight snow. You can fight back, though, by using common sense and frequent car washes.
If there is one thing that road salt loves to eat, it is cars. That’s right, the life-saving chemical that helps to keep roads open throughout the Snowbelt (Northeast and Upper Midwest, primarily), is also addicted to cars. Salt just loves to get into all the nooks and crannies that you cannot see and begin its feast on your vehicle.
Salt, if left on your vehicle, loves to eat anything metallic. For instance, your car’s brake lines are usually made of metal and since they are right there where the salt meets the road, they are, many times, among the victims of salts acquired taste for cars.
That’s not all. Because your car’s undercarriage is open and exposed to salt, sand, snow and everything else that’s on the roadway, it is also exposed to the same elements. Unless parts of your car’s undercarriage of totally sealed – a rare occurrence, if it happens at all – then anything that is put down on the roadway can splash up and become lodged somewhere.
Because you cannot see the undercarriage, unless you have your car put up on a lift or unless you have a pneumatic jack on which you can lift one end of your vehicle safely and look underneath, while you lie on your back, it is impossible to see exactly where salty water and other grime lands. It may be, as noted, on the brake lines or on the muffler or exhaust system. Or, it may land on the coil springs or even on the shock absorbers. As soon as the salt is deposited, it begins its work, having a banquet on the metal parts on which it has landed.
What is worse, though, is when the salt and grime land on places that are well out of sight such as behind a plastic shield or on a fairly inaccessible – almost hidden – spot. In each of these instances, you have no clue as to whether anything has been deposited in the first place. You have to assume that because you have taken your car out and are driving it that it has had salt exposure.
It’s funny that salt, an important safety tool, is also an expensive, but corrosive solution. The National Association of Corrosion Engineers estimates that salt corrosion costs the nation $267 billion per year in automotive damage. That is a huge figure. To put it in perspective, based on a U.S. fleet size of 300 million vehicles, it costs about $800 per car a year, a hefty price to pay.
Though it is a costly tool, salt is also a necessary one because it is the only way to ensure that snow and ice are melted off the roadway during bad weather. And, even salt has its limitations. At temperatures approaching zero (Fahrenheit), standard salt (NaCl) begins to lose its effectiveness. It does cause ice and snow to melt, however, since the temperature is so low, the water refreezes almost instantly. There are other formulations, and calcium chloride and magnesium chloride, for instance, that work at low temperatures but even they have their limitations. And, since they are salt-based, when splashes occur you are back in the same situation.
(Notice that many times salt and grime are paired. The reason is that many municipalities use sand, effective down to about 10 degrees, or sand mixed with salt. The sandy grit left on the roadway after a snowfall is heavily impregnated with salt so that when the grime becomes lodged within your car’s frame or an undercarriage member it concentrates the corroding action of the salt, acting much like a magnifying glass in the sun, so that wherever it is deposited corrosion is enhanced.)
It may seem like there is no hope, however, there is. Using time and common sense, you can protect your car from salt-based damage. The key here is speed. Everything you do should be done as quickly as possible after your car’s exposure to salt and grime.
Although it may seem futile or like it is a waste of money, you should have your car washed and waxed as quickly as possible after a snowfall where you have been out driving. The reason is that a good wash is the only way to remove the salt from your vehicle as the water and cleaning agents melt salt deposits and wash them off your car. Once the car is washed, you then have to ensure that the surface is sealed against further damage so it is advisable to have the best possible wax application available used on your car. Once it is dried, the wax will help to seal whatever surfaces it falls on.
When you are picking the car wash where you will have your vehicle cleaned be sure that the site offers an undercarriage wash. If not, find a car wash that does offer an undercarriage wash. An undercarriage wash is important because it is the only way available to you to clean salt and grime deposits off that hidden area of your car. The undercarriage wash is able to reach all of the spots where salt has been deposited and it washes the chemical out.
Of course, once you pull out into traffic on leaving the car wash the salt will again begin to build up as the roads will likely be wet or snow-covered if your area has had an extended snowstorm or period of cold and snow. This means that you will have to have your car washed again fairly soon. Here is where it looks like an expensive gesture of futility if you have your car washed every three or four days. If you stretch it to five days it is better since you will have a longer period between washes. It will help keep your costs down, a bit. In the longer term, though, frequent washings will ensure your car remains corrosion-free for a long time.
Regular car washing and waxing with a good undercarriage wash is the best defense against salt-based corrosion, however, there are some other things that you can do to keep your car as salt-free as possible. They include:
Avoiding large puddles of water, if you can. Large puddles during the winter are likely to contain nothing but salt-contaminated water and so if you want your car’s body and undercarriage to last, you have to avoid these puddles.2
Try to find as much dry pavement as possible to drive upon. It is possible to do this, believe it or not. The way to find dry pavement is to look ahead and watch where the majority of cars travel. You should be able to see it easily as the areas where the majority of cars travel looks wet. Right beside the wet lanes, you will likely see a bit of dry road. To place your car on the dry tracks, you have to concentrate and keep the vehicle there. It is possible to do, but it does take some work.3
If you can avoid taking your car out of the garage or your parking spot, do so and work from home. If your car isn’t moving it isn’t being swamped with salty, grimy road residue.
Finally, once you have cleaned your car’s body and undercarriage and once they are well waxed, it is a good idea to vacuum the interior to remove grit and gravel. This will not only cause added wear and tear to your vehicle’s upholstery and carpeting, but it also doesn’t look very nice.
Marc Stern has spent more than 40 years in and around cars. His work has included answering motorist questions, motor vehicle reviews and evaluation and writing dealers, consumer and industry news pieces. In addition, Mr. Stern has contributed to well-known automotive publications including Popular Mechanics, Mechanix Illustrated, AutoWeek and Old Cars Weekly, among others.