December 4, 2023

As a resident of Lawrencetown, N.S., just east of Halifax, David Giles’s home is enveloped by the salty air of Cole Harbour and the Atlantic Ocean.

“A car just parked in my driveway [for a few months] can get rust on the rotors,” he says. It’s one of the reasons that Giles, a training and development manager at All EV Canada, a used electric vehicle dealership in Nova Scotia and New Brunswick, highly recommends all cars, including EVs, be rustproofed – even though it may jeopardize the manufacturer’s warranty.

That’s why Giles has developed special processes for rustproofing EVs across 28 brands, from Toyota to Tesla. The EVs are disassembled, with all covers, fender wheels and cowls removed, then washed, cleaned, dried and the paint touched up. Each EV model has a checklist of specific steps and procedures for application of the rustproofing product.

Rustproofing can take anywhere from three to seven hours for one vehicle and cost up to $700 for the first application. Giles says he uses only one-third of the product that conventional spray-type rustproofing shops use. He says his product is not only “environmentally friendly” but his process ensures the product is kept away from battery and electrical components. These are made from plastic and aluminum, so spraying rust protection on them would make no sense anyway, he explains. He says the ingredients in his formula have been approved for use on ships while in dry dock to inhibit corrosion and that when the vessels are returned to the water, the residue has no harmful effect on wildlife. The product is also clear, so it doesn’t obscure the high-voltage orange cables that technicians and first responders are trained to look for.

Giles notes that manufacturers provide an e-coating – a substance that binds to the metal for extra protection after the car is painted – on EVs, which is supposed to protect the vehicle in ideal conditions. But he says our harsh Canadian winters may require something more. “In Canada, we have salt and brine, and we don’t have perfect roads,” he says. Because the manufacturers have already applied an e-coating on vehicles, rustproofing by a third party may jeopardize the vehicle’s warranty.

“A [manufacturer] isn’t going to endorse a rust-protection product because they can’t control that product,” he said.

Although salty air and salty roads can cause rust, salt alone won’t cause the battery to burst into flames, as was the case with some waterlogged Florida EVs after Hurricane Ian earlier this year. “A fully submerged vehicle can have some water intrusion and, mixed with salt water, can cause corrosion and shorting after it dries,” says Giles. “Of the 3,000 EVs that were flooded in Florida, only a small handful were involved with thermal runaway fires.”

However, the day-to-day exposure to roads that have been salted can wreak havoc with metal as well as other components of a car.

“Manufacturers try to have water-tight seals, but can’t protect against condensation,” says Trevor Hutcheson, a sales manager at Canadian Krown Dealers Inc., a co-operative group of rustproofing businesses. In Ontario, roads are sprayed with a mixture of magnesium and calcium chloride together with a binding agent that keeps the tacky solution on the roads. When it attaches to metal components, he says, it’s difficult to remove.

EVs are regularly rustproofed at Krown, with the same oil spray that’s used on gas-powered cars. “The structure of the vehicle is essentially the same,” says Hutcheson. “The different part relates to how properly you look after the electrical components. We do spray, but our product does not contain solvents, and has a very high dielectric strength and therefore does not conduct electricity.” He says Krown’s product uses a recycled petroleum base along with additives that contain no solvents, are non-flammable and non-toxic.

According to Hutcheson, the Krown rust protection product is designed so it can be sprayed on electrical connections to displace moisture and is used for both EVs as well as gas-powered vehicles.

He says the process can void a warranty if there is an issue with how the rustproofing product is applied. The company drills small holes into the vehicle’s body panels to allow the product to be sprayed on the inside of the doors, rocker panels and so on. “If we make a mess by drilling a hole, the manufacturer isn’t responsible for it. They’re 100-per-cent right; they shouldn’t warranty somebody else’s workmanship,” Hutcheson says.

A number of manufacturers confirm that rustproofing EVs can void their warranties. “We do not recommend or endorse any additional ‘rustproofing’ and spell this out within the vehicle’s owner’s manual as follows: ‘Your Volkswagen model is corrosion protected at the factory. You do not need to purchase rustproofing,’” Thomas Tetzlaff, manager of public relations at Volkswagen Canada, said in an email. ”For customers seeking additional corrosion protection from outside parties, application of this product (on our EVs or conventional vehicles) will not of itself impact the warranty, however, if the cause of any future corrosion (or other component failure) is deemed to be the result of either the product applied, or the method in which it was applied (such as drilling holes in the vehicle to apply product), Volkswagen Canada will have the right to reject the warranty claim.”

Yusuf Dassut, manager of warranty supports at Hyundai Canada says much the same: “In the case of rustproofing, Hyundai Canada does not currently recommend the use of oil spray or electronic rust inhibitors on vehicles with electrified powertrains, as they may cause faults or component failures, which would not be covered under warranty.”

And Michelle Burnham, senior manager of product communications at Chevrolet Canada, says, “Application of after-manufacture rustproofing products may create an environment which reduces the corrosion resistance built into your vehicle. Repairs to correct damage caused by such applications are not covered under new vehicle limited warranty.”

So even though the harsh cold, salt and brine of a Canadian winter can potentially wreak havoc on EVs, rustproofing carries risks.

Yves Racette, director of program development at NexDrive, the EV division of NAPA Autopro, a chain of auto repair shops, sums it up. “You have to be really careful about rustproofing an EV.” He recommends anyone providing rustproofing services warn EV owners that it could void the warranty.

He points to electronic rustproofing, a device that can send a weak electrical signal into the vehicle to ostensibly neutralize the chemical reaction that leads to rust. Although it’s the same technology used on boats and bridges, it can create a conflict with hybrid and EV systems. “We don’t recommend it.

“With an electric vehicle, the manufacturer doesn’t know the person who is applying it. The manufacturer doesn’t know what the rustproofer’s knowledge is about where to put it and not to put it. It’s not like icing a cake. You can’t put it everywhere.”


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