How often to wash a car in Winter?

I had my car detailed, and detailer said infrequent washing was best for car in winter. I live in Minnesota. He believes that water penetrates window seals and leads to eventual door rust

This sounded nuts to me

I have always washed frequently to get rid of salt residue. I also leave my winter car outdoors to avoid freezing and thawing which I believe is hard on body. No much rusting or oxidation takes place at zero!

What are your thoughts?

Thanks in advance


I have a friend who has been driving for over 45 years and still owns “almost” every car, motorcycle, tractor, truck he ever purchased…and they are all rust free. He has more large garages than I have vehicles and swears he has put less into his vehicles than I the last 40 years. He lives on a dirt road in the North East salt belt and commuted 50 miles per day in this area in 20-25 year old VW Beetles and Rabbits over the 25+ years we worked together. I trust his judgment on vehicle maintenance. He:
1 keeps them garaged or under cover when not used winter or summer.
2 Rinses them after each use if dirt or salt were present while driving.
3 Keeps newspaper or water proof barrier between shoes and floormats
4 waxes cars he uses usually just once or twice a year depending upon use
5 starts and runs all vehicles (40 +) regularly
6 discourages regular driving by others in use of vehicles in family except by trusted son other then their own
7 rust preventative treatments with oil (the procedure I’ve mentioned here) every one to two years depending upon use frequency
8 regular mechanical service by owners manual recommendation (usually by himself)

He is an environmentalist and feels he is more so with his routines than letting his cars rot and replacing them more frequently. Even his tractors look “show” an hour after hard use. BTW, he treats friends and family with the same care and thoughtfulness.

My feeling on your question. Water does collect at the bottoms of metal seams which even drain holes can’t take care of completely. Rain and pollution will collect as well as road salt so diluting with fresh water is worthwhile. Limit oxygen to prevent rust formation by “sealing” with oil treatments. Anything else more substantial will dry out over time, crack and collect and retain moisture causing more corrosion. As far as leaving outdoors, you have to way the damages that can occur from each. Summer sun is a huge culprit to car’s finish and seals, worse than in winter. Rust prevention, if you keep a car that long, is a maintenance item, not just an avoidance item.

Contrary to what you will hear by some; “all cars are rusting”. Manufacturers just do a better job of delay and or hiding that fact of late. Check your recent recalls…

Wash it when you want to.  Washing may wash some salt out, but then it might just get the salt wet (Dry salt does not cause rust).  

When the temperature is cold enough to keep the snow snow and not met it, the salt is not causing any problems wet or dry. 

Let's face it is going to get salt on it faster than you can take it off anyway.  Modern cars are well protected by design and don't have the problems the cars did when I was a kid.

Denver uses mag chloride on roads just before a storm and cinders/sand during the storm. I wait until our solar snow removal system clears the roads. If it’s over 40 degrees, I get out the bucket and hose for a hand wash. No soap on body panels, just for wheels and tires. If its under 40 degrees, my driveway will ice up so I hit the hand car washes – pressure hose and foaming brushes are not the best but better than leaving mag chloride on the car.


“I have always washed frequently to get rid of salt…” Sounds like your doing fine John. I give it a wash on warm winter days so we don’t end up with doors frozen shut and power windows iced in. Do that and someone in the family will keep punching the the down switch to see if the motor can break it loose. It can’t. Wouldn’t depend on “zero” too much. Salted roads mean liquid. Liquid means salt solution getting into every nook and cranny under the car - which is where I point my winter wash nozzle.

In Minnesota, I suspect the roads are wet with salt and snow run-off most of the time during the winter. So if you drive the car regularly, washing it is a complete waste of time as the destructive salt spray has penetrated every joint and you are never going to wash it out…Now most cars have fender lips that catch and hold salt saturated wet sand. You might TRY to keep those areas cleaned out and avoid the classic rusted-out fender eyebrows…

I have lived in MN and WI my whole life and salt in the winter is a definite issue. Here’s what I’ve been led to believe from experience and from what I’ve been told:
Salt will do more damage when wet and warm. Take road conditions and temp into consideration when considering a wash. I’ve also been led to believe that parking outdoors does have its advantages. Especially if you have a heated garage, that heat can accelerate salt’s ability to rust. I’ve also heard that even in non-heated garages, the air temp can increase when a warm vehicle is parked enough to make a difference, but it’s hard to say on that one. I will say that my grandpa’s old Olds that was garage-parked rusted far faster than any of the cars my dad and I have always left out in the winter. Some of this may depend on how long you wish to keep your car. Some people may not care if their habits lead to it rusting faster since they’ll be trading it in before body rust is a real issue anyhow. I’m not in that camp, though. Another point to consider is that some vehicle designs lend themselves to certain rust issues in the long run if certain areas accumulate debris and moisture more than they should.
In conclusion, I think washing is a good thing in the winter overall. Be sure to get the undercarriage cleaned as that can be overlooked at times.
Remember, rust can only be contained, not stopped. As the Neil Young song says, “Rust never sleeps,” unless you’re putting a car in a perfectly controlled environment. Most people can’t do that.

BTW have you noticed that the parts that get washed are usually not the same parts that rust.

Note: many car washes re-cycle the water, so you end up spraying your car with salty water.

Neil Young is a smart man and the detailer is absolutely right about water penetrating window seals that leads to door rust, but so doesn’t road salt with spray. Rust never occurs from the outside if the finish remains unbroken. My first SAAB 99 (71) had one of the best engineered bodies for water penetration and drainage and have seen nothing better since. IMO, unibody construction lends itself to easier rust preventative measures then body on frame. In addition to doors,protect the sills, inner/outer fender joints and rear quarters from the inside…the areas of biggest concern which can vary from one make to another. For body on frame trucks, it’s judicious use of “red grease” with a foam brush, painted on to important non heat exposed frame areas. Otherwise, move to area where rust has more trouble taking hold or trade your car before rust “appears”. Once it does, it’s value drops out of sight regardless of mechanical maintenance.

Dry salt also doesn’t tend to stick to your car. And if the salt is dry, it means it’s too cold for salt to work, so it’s pointless.

It’s actually ALWAYS pointless, since there are other options (sand, gravel, dirt) that work just as well, but in different ways.

The Salt Institute is the enemy of all northern motorists.

Tape over the window seals before you wash the car. Problem solved.

Until you peel the tape off and drive in the rain.

[b]“Note: many car washes re-cycle the water, so you end up spraying your car with salty water.”

Thanks for the reminder, Joseph E Mehan. That’s one reason I hand wash my cars. The other is the minute scratches car washes can put into the finish.[/b]

Just wash it when it is dirty and you want it cleaner.