How Garaging a Vehicle Can Cause Rust in Winter | and How to Prevent It!

Many people regard the use of a garage as the best place for a vehicle. Perhaps shockingly, that’s just not always the case.

black toyota vehicle on snow field at daytime with salty road

Did you know that garaging a vehicle can cause rust? While it is true for summertime garaging as well, it’s a lot more likely during the winter. Why? Salt. Salty roads after wetness, to be more precise. Wet salt from melting snow, slush, sleet and general rain.

So how does garaging the vehicle during these conditions make the risk of rusting worse than if you were to park outside? Let’s look a little closer.

We get salt all over our vehicles

It’s winter time. The temperatures drop enough to flirt with the freezing points. Bridges and overpasses tend to freeze faster than roads with earth beneath. So, the state, county or city will treat the roads with salt, sand, and other corrosives. These treatments, while dramatically helping us keep traction on the roads during inclement and icy road conditions, wreaks havoc on our vehicles metal parts.

Until better technology is innovated, salting roads in colder climates is a fact of life we all must accept. Fortunately, if you’re aware of what’s being coated all over (and under) your vehicle, you’ll be more prepared to counter the negative effects this fact of life has on your vehicle.

Wet salt is what’s harmful – NOT dry salt

In order to better understand the concept that garaging a vehicle can cause rust, it helps to understand this one point first: Wet salt is what causes the rust. It is not dry salt. Wet bunched up laundry is what causes the mold and mildew. Not dry bunched up laundry. Wet sides of the house are what gets the green gunky buildup on the sidings and brick. Not the dry sides.

aerial photography of snow covered trees on a possibly salty road which can cause rust
Photo by Ruvim Miksanskiy on

Moisture is what is needed in order for the chloride of the salt compounds (NaCl) to become corrosive against metal. So if we understand this aspect, the rest of the article becomes a whole lot easier to understand. It will change your entire winter vehicle garaging lifestyle. For the better.

Let the snow/slush stay frozen – if you can

When a driver arrives to the garage after driving on freezing, snowy and/or slushy salted roads, they have a choice. They may park in the garage, which will likely be 10 to 30 degrees warmer than the outside air. Or they can remain parked outside in the freezing temps. Now let’s look at what happens if the driver elects to park in the garage to let it all melt away, versus parking where the vehicle can freeze up or melt with the outside world.

Parking the salty, snowy, slushy vehicle in the garage

When the driver parks the snowy/slushy vehicle in the garage, which is likely filled with salt, the vehicle begins a melting process. Any crystals or ice accumulated in the wheel wells or anywhere else on the vehicle will now melt, forming a wetness. This water (moisture) will now interact with the chloride of the salt (NaCl), and activate corrosive properties. The driver shuts the garage door. Assuming no fan or air conditioning is in the garage, the driver has now decreased the ventilation of their garage. The garage remains a damp dark place where the wet salt is free to do its evil deeds.

The vehicle now has corrosive wet saltwater resting all over and under the vehicle, in crevices, etc. With little to no adequate ventilation, the water doesn’t dry for a long period of time. Water doesn’t evaporate as quickly in cold as it does in warm temperatures, so it lingers for quite a while. In this case – the salty water remains in it’s corrosive form for many hours to come.

Hopefully it’s becoming more clear that garaging a vehicle can cause rust.

Parking outside where it’s freezing (or melting) with the outside world.

If the same driver in the same salty circumstance were to have elected to park outside, the corrosive effects would’ve been limited. Parking outside in freezing weather would have kept in ice form any built up snow or slush, and would have froze up any wetness caused by driving. As the liquids would’ve frozen back up into ice form, the wetness (which is the activator of salt’s corrosive effect) would’ve been, deactivated.

But let’s say the outside temperature isn’t freezing. It’s cold, but the sun and temperatures are going to cause the vehicle to get wet anyway. Being outside, the vehicle will in fact melt it’s salty water. But since the vehicle is outside, it has plenty of ventilation to dry itself in a minimal time as possible. Winds will speed up the drying process. Air will be able to circulate around and under the vehicle, drying up as much as nature can.

When the salty water has dried, what will remain is….salt. Just the salt. But it will be dry salt. And as we know, without moisture activating with chloride, salt is not corrosive to metal. So, that driver would be in better shape as time moved on, versus the first option of using the garage.

Once the vehicle is fully dry, even if still salty, the driver should feel free to park inside the garage.

No option BUT to park in the garage

Some drivers may not have much of a choice but to park in a garage after driving on snowy or wet salted roads. In this case, these drivers should do as much as they can – with what is available to them – to minimize the negative effects of the corrosive wet salt. Some tips and ideas that may help are:

  • Keep the garage door open to allow for ventilation to assist drying
  • If available, open windows
  • Use a fan (box fan, etc) to circulate the air
  • If using a fan, attempt to angle it toward the outside air, and to areas and crevices that need assistance in drying
  • Use a leaf blower to blow off loose wetness
  • If running water is available, rinse the vehicle throughly, hitting crevices, door jambs, undercarriage, etc.
  • In a best case scenario, wash the vehicle with soap and water and dry as best you can.
  • Pop open trunks, hatches or hoods to allow for the jambs to dry
  • Use a dehumidifer, especially in cases where the garage door must remain shut
  • Use a heater, but only if you have a way of ventilating and/or dehumidifying the air – otherwise you are only letting the salt get corrosively wet faster and stay corroding longer

Wash your vehicle on a regular basis during winter months

Experts agree that, during winter months, washing the vehicle every 7-10 days regularly will help combat the effects of salt throughout the season.

If using public car washes, be sure to elect for undercarriage wash and sprays. While using self service spray bays, don’t forget to thoroughly wash under the vehicle. If at home, a pressure washer with enough force to carry volumes of water underneath the car and into tight spots will help dilute built up salt spots.

Areas of the vehicle to concentrate on for salt build up

It’s one thing to wax and wash your car regularly, but you need to focus on areas less seen and directly washed during these salty and corrosive winter months. Let’s face it, you probably have never waxed your undercarriage nor inside your door jambs. Pay special attention to these areas – where salt builds up and is less often cleaned and waxed:

red suv on snow covered ground with salt buildup in the jambs
Photo by Brett Sayles on
  • hood jambs/jambs surrounding engine bay
  • rear trunks/hatch jambs
  • door jambs
  • rocker panels (areas beneath the doors/passenger area)
  • (for trucks) the area between the cab and the bed
  • between the bumpers and the body of the car
  • The crevice all around the windshield and rear windows
  • The bottom area of the windshield has vents and drains – thoroughly rinse those areas
  • mufflers – do not spray directly into the muffler
  • catalytic converter (they are expensive, protect it/them!)
  • wheels, and behind wheels, like hubs, and rotors
  • suspension pieces – especially where the bolts meet the parts
  • look up the proper way to spray an engine bay, and spray that thoroughly
  • see a pattern here – basically EVERYWHERE that isn’t electrical. where salt can build up
  • crevices, crevices, crevices.

A useful tool in more ways than one

An air compressor, like this one from California Air Tools, with a fine spraying attachment is great for blowing out sitting water from crevices not easily seen nor dried. Every person should have one for more reasons than this.

WD-40 and certain lubricants should be applied to joints and metal bolts regularly. This helps dissuade corrosion and to inhibit seizing of bolts due to corrosion.


Hopefully it’s clear now why garaging a vehicle can cause rust. More, we hope you found some new tips and insight as to how to prevent, inhibit, and/or rid your vehicle of as much salt as possible. Your vehicle is expensive. Protect it.

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