Washing your car after a snowstorm

Wait for the roads, not the sky

The snow stopping is not the signal to wash. For a day or two after a storm the roads are still slushy and the plows and salt trucks are still working, so a clean car comes back grey within one drive down Veterans Memorial Pkwy or the 401. The better moment is when the main roads have gone from wet slush to damp or dry, usually a day or two later.

Don't leave it a week either. The slush that packs into the wheel wells and under the bumpers is full of salt, and it sits against the metal while it melts. If a thaw is coming, it's worth washing soon after it starts, because that's when the salt is wet and moving into seams.

Clear the car before you drive over

Take the snow off the roof, hood, trunk and lights before you go anywhere, not just the windows. A slab of snow on the roof slides onto the windshield the first time you brake, and it can come off on the highway and hit the car behind you. It also blocks the wash from reaching the roof.

• Brush the roof, hood and trunk lid down to the paint, using a soft brush, not a scraper
• Clear headlights, tail lights and the camera or sensor areas on the bumpers
• Lift the wipers off the glass if they are frozen down, and free them gently
• Knock loose clumps of slush out of the wheel wells by hand, not with your boot, which can crack the plastic liners
• Check that the mirrors move and the windows close properly

Put the effort into the underside

After a storm, the paint looks the worst but the underside is where the damage happens. Brine and salty slush get into the frame rails, the rocker panels, the brake lines and the back of the subframe, all places you never see. Rust in Ontario cars usually starts in those hidden seams and works outward, which is why a car can look fine on top and fail a safety inspection underneath.

If you only choose one thing in January, choose an underbody rinse. At Fast Lane, the Full and Luxury washes both start with an under-car spray, and the Luxury Wash adds a rust inhibitor after it. A rust inhibitor applied at a wash is a light treatment, not a replacement for proper rustproofing, but it's a reasonable addition when the car is carrying a lot of salt.

After the wash

Snowstorms usually come with cold, and a freshly washed car will freeze at the doors if you leave the water in the seals. Before you drive off, open each door, wipe the rubber and the edge of the door with a towel, and work the locks and handles a couple of times. Run the defrost for a few minutes and turn the wipers on once to clear the glass.

Then keep an eye on the forecast. Several storms in a row with freeze and thaw in between is the hardest stretch of the year on a car, and a wash after each one does far more good than one big clean in March.