A clean car in January can feel pointless. You wash it on Saturday and by Monday it is gray again. But the white crust that builds up after a few trips on treated roads is more than cosmetic. Road salt and liquid de-icers cling to metal and keep working on it long after the snow melts, which makes winter one of the most important times of year to wash your car.
At a Glance
- Salt and de-icing chemicals speed up rust on the body, brake lines, fuel lines and underbody.
- Wash when temperatures are above freezing, and dry the car thoroughly afterward.
- Choose a wash with an underbody rinse whenever you can.
- Waxing before winter gives paint an extra layer of protection.
What Salt Does to a Car
Road crews use salt and brine to keep roads passable, and they do their job well. The trade-off is that salty water is very effective at corroding steel. It splashes into wheel wells, coats the underside of the car and settles into seams and crevices you never see.
Over time, that can mean rust on body panels and rocker panels, but the bigger concern is often underneath. Brake lines, fuel lines, exhaust components and suspension mounts are all exposed. Corrosion there is not just ugly; it can affect safety and lead to costly repairs. Regular washing removes the residue before it has a chance to settle in.
Picking the Right Day
Temperature is the main thing to watch. When it is below freezing, water can turn to ice on contact with the car, sealing doors shut and freezing locks, handles and rubber seals. A good rule is to wait for a day above 32 degrees Fahrenheit, ideally somewhat warmer and sunny, so the car can dry before nightfall.
Timing also matters. Washing right before another round of salted roads will not last long. Try to wash after a storm has passed and roads have started to dry.
Pro Tip
Let the car dry before you drive on wet roads. Salty spray sticks to damp surfaces, which can undo much of the wash.
Automatic, Touchless or At Home?
| Option | Good for | Keep in mind |
|---|---|---|
| Touchless automatic wash | Quick salt removal without brushes touching the paint | Choose a package with an underbody rinse and a blower dry |
| Soft-cloth automatic wash | Removing heavier grime | Make sure the car dries well before you park it outside overnight |
| Self-serve wand bay | Targeting wheel wells and the underside yourself | Wear waterproof gloves and dry door jambs and seals by hand |
| Garage sponge bath or waterless wash | Light cleaning between full washes | Will not reach the underbody well, so pair with an occasional full wash |
How Often Is Enough?
There is no single schedule. If you drive daily on heavily treated roads, washing every week or two keeps salt from building up. If you mostly work from home and drive a few times a week, every few weeks or once a month may be enough. A good cue is visible salt film on the lower doors and rear of the car. If you can see it, it is time.
After the Wash: Avoiding Frozen Doors
Even on a mild day, temperatures can drop sharply after sunset. A few quick steps help keep you from getting locked out of your own car the next morning:
- Wipe down door jambs, rubber seals and the edges of the trunk with a microfiber towel.
- Open and close each door a few times to break any thin film of ice before it sets.
- Dry around keyholes and handles if your car has them.
- Apply a thin coat of rubber protectant or a little cooking oil to door seals before a freeze is expected.
If a door does freeze, do not yank on it. You can tear the seal or break a handle. Warm the car with a remote starter if you have one, or use a lock and seal deicer, then try again.
Wax and Other Protection
A coat of wax or paint sealant applied in the fall acts as a barrier between salt and your paint. Most waxes need moderate temperatures to cure properly, generally around 50 degrees or warmer, so do it before the cold sets in. If winter is already here, wax in a heated garage or wait for a warm spell.
Other helpful steps include all-weather floor mats to catch salty slush inside the car and an annual underbody inspection to catch corrosion early.
Insurance Angle
Rust and corrosion are generally considered wear and tear, which auto policies typically do not cover. Keeping salt off the car is one of the simplest ways to protect its condition and its value, including what it might be worth if it were ever totaled.
Frequently Asked Questions
Is it bad to wash your car when it is below freezing?
It is generally best to avoid it. Water can freeze in locks, seals and door handles. Wait for a day above 32 degrees and dry the car well.
Does an underbody rinse really help?
Yes. The underside collects the most salt and has many exposed metal parts, so rinsing it is one of the most valuable parts of a winter wash.
Can I wax my car in winter?
You can, but most waxes cure poorly in the cold. Wax indoors or on a warmer day, or apply protection in the fall before winter starts.
Protect More Than the Paint
A good wash protects your car’s finish. The right policy protects the rest. Talk with Callicott Insurance Agency about auto coverage that fits how and where you drive.
This article is for general information only. Coverage varies by insurer, policy and state; review your own policy or talk with a licensed agent about your situation.