Northern Alberta Institute of Technology

How and why to wash your vehicle in the winter

If you had the choice between a $10 to $20 car wash and an $8,000 full-body paint job, what would you pick? Most vehicle owners would say the former but, given the harsh winters, most Albertans are on a crash course with the latter.

During the cold months, “People don’t wash vehicles often enough,” says Scott Sinclair, Auto Body Technician chair (and class of ’93). “The grime that is on the road is extremely corrosive to your paint.”

To be kinder to our cars and trucks – and ultimately our bank accounts – we asked Sinclair about what to do to keep rust at bay. Proper washing is a skill that’s vital to his trade, and the first thing his students learn to do. Here’s Sinclair’s lesson for the rest of us.

How to wash

Spend about 20 minutes once a week on a hand wash. Always start at the top of the vehicle and work your way down using hot, soapy water. Watch the colour of the water running down the drain. “You should wash until that dirty water is gone,” says Sinclair.

Worried about your doors freezing shut? Dry out the door jambs with a clean microfiber cloth or disengage your interior lights and leave the vehicle doors open overnight in the garage.

“Rust has to be sandblasted.”

Problem spots

Wheel wells, rocker panels (the strip beneath the door), body-side moldings and door jambs are among rust’s favourite spots to take root. Road grime can collect in, around and on each of these parts, says Sinclair.

Get the spray nozzle in close and wash until the water runs clean. If you go for a touchless wash, pay a little extra for the option that sprays the undercarriage.

Also, don’t be afraid to soak the engine, starting at the underside of the hood (avoiding any insulation) and working down, as you would with the entire car. “Twenty-plus years ago vehicles were very sensitive to moisture under the hood,” says Sinclair. “Now they’re not.”

Cleaning the engine prevents corrosion and can also reveal maintenance issues, such as leaks. “When you have a clean engine, you can spot things very quickly.”

Big no-nos

Avoid storing your vehicle in warm places in the winter if it isn't dry and clean. Especially in a small garage, but even in a heated parkade, melted ice and snow brought in from the road can create a humid environment that encourages corrosion. “You should keep the temperature just above 0 C if possible,” says Sinclair.

Ironically, the car wash itself can be bad. “A big no-no for your vehicle is the scrub brush. It’s so harmful.” These tools contain the dirt and grime of their last washing job, making them like sandpaper, says Sinclair. If you use them, thoroughly spray them out first. For the same reason, never use them on your car without having washed all the abrasive material off the body.

And that big spinning brush at the touchless wash? Avoid it, too.

The product of neglect

Once you see rust, it will have already spread unnoticed beneath the paint, says Sinclair, and require repairs. “Rust has to be sandblasted,” says Sinclair. If it has eaten holes into the body, the panel needs replacing. “It gets very expensive. So it’s best to do the preventative maintenance up front.”

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