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Gritted roads: how to protect your car from winter salt

Advice on how road salt can damage cars

You can't always guarantee snow in the UK, but the gritters are always out in force when temperatures are predicted to get close to freezing, raising the risk of ice patches on the roads.

While reducing the risk of skidding is desirable, of course, the corrosion caused by the salt in the road grit is not.

Left on unprotected surfaces, the salt will rapidly promote rusting on metal parts. Any chips in the body paintwork will turn into rust spots, and underneath, any metal surfaces without some form of protection will gradually corrode, waiting to be discovered at the next MOT inspection.

While exposure to the salt-laden spray from wet roads in the winter is pretty much unavoidable, there are a few steps that can be taken to help slow down the deterioration process.

Salt being spread on a road in winter

How do I stop road salt damaging my car?

The first item on the damage-limitation list is obvious enough: wash the vehicle frequently.

I know it’s a chore on a cold day to go outside, get out the hose pipe, wash the car, then clear everything away again, only for it to get dirty again next time you head out, but that washing process not only removes the salt-laden dirt, but also applies a layer of protective wax – as long as you use a high-quality car shampoo.

The wax layer probably doesn’t last long, but it’ll be good enough for about four weeks of protection. This means that you’ll need to wash the car maybe four times over the winter. Doesn't sound so bad now, does it?

Using a pressure washer to clean a car

How do I protect the underside of my car from salt?

The second process I use does take more effort, but only needs to be done once a year or less.

It involves raising the vehicle, supporting it on jack stands, then removing all the wheels and wheel arch liners, and applying liquid underbody protection.

Why remove the wheel arch liners? Although they stop stone chips damaging the underbody sealant and paintwork, they also trap road/mud between the liner and the vehicle body. The mud holds moisture, and in winter it's salty moisture – well, you get the picture.

Using a pressure washer, remove any loose mud and debris from the vehicle underside and wheel arches. There’s no need to completely remove all the dirt - just the loose stuff because the anti-corrosion spray will bleed into the surface, finding all the little nooks and crannies.

Allow the surface to dry, then using the hand-powered spray gun provided, liberally spray the anti-corrosion liquid under the vehicle, covering everything except the brake discs. 

Obviously, there are many different types of protection sprays available, but the one I use is safe to use on metal, plastic, rubber and electrical connectors – so I spray it everywhere!

How much does underside protection cost?

The protectant won’t wash off easily, and some manufacturers even claim their product resists pressure washers.

It’s a very messy job that takes about two or three hours, but it’s satisfying to know that there’s a barrier between your car and the salt.  

Total costs vary enormously, but the kit I use includes the spray gun and enough protectant for two cars, and costs around £80. 

The only downside is that the liquid included in this particular kit is based on Lanolin, so the car smells a little sheepy for a day or so!