A mechanic inspects severe rust beneath an older car in a winter repair shop, illustrating road salt corrosion.
Cost of living, economy

Your Car’s Engine Still Works. Road Salt May Decide When You Replace It.

Americans are keeping their cars longer to avoid expensive replacements. In colder regions, winter corrosion can make that decision impossible, even when the engine still runs.

A Canadian reader recently told me that he had replaced a car that was still running well. Its engine had not failed. Years of winter road salt had damaged the body badly enough that keeping the vehicle no longer made sense.

He left the comment beneath one of my articles about Americans holding on to old cars.

I had been examining the rising cost of replacing vehicles. Readers described driving cars for fifteen or twenty years rather than accepting another expensive loan. The Canadian experience introduced a problem I had largely overlooked.

In Karachi, an old car with a dependable engine can remain useful for years. Coastal humidity causes corrosion here too, but we do not spread salt on our roads to melt winter ice.

A Canadian winter can shorten a car’s life in a very different way.

America’s Cars Are Getting Older

The average age of light vehicles operating in the United States reached 12.94 years in 2026, according to figures released by the Auto Care Association and MEMA Aftermarket Suppliers.

Passenger cars averaged 15 years. Light trucks averaged 11.9.

The organisations estimated that Americans operated 294 million light vehicles. Some 29.1% were at least sixteen years old.

High replacement prices help explain why owners continue driving ageing vehicles. Improvements in manufacturing also allow many cars to remain useful for longer.

But an old car’s continued operation depends on more than the distance recorded on its odometer.

A vehicle driven through years of salted winter roads faces conditions that another car of similar age may never encounter.

Winter Road Salt Can Damage a Car That Runs Perfectly Well

Highway authorities use salt to help control ice during freezing weather.

It serves an important safety purpose. Salt lowers water’s freezing point, although its effectiveness depends on temperature and other road conditions.

The trouble begins when salt mixes with moisture and reaches exposed vehicle metal.

Corrosion can develop beneath the car, where owners rarely look. Damaged protective coatings allow the chemical process to attack vulnerable components.

The affected areas can include brake lines and parts of the suspension. Severe rust may also weaken structural metal that supports important vehicle components.

A driver could have a well-maintained engine while the underside of the car deteriorates.

In February 2026, AAA warned that road salt could cause damage that remained hidden until the vehicle needed inspection or repair.

The organisation also noted that insurers generally treat gradual corrosion as wear and tear rather than covered accidental damage.

A vehicle owner may therefore face the repair bill without help from an ordinary insurance policy.

Source: AAA, February 18, 2026

Americans Have Already Paid Billions for Salt Damage

AAA examined the financial burden in a survey published in 2017.

It estimated that American drivers had spent $15.4 billion repairing salt-related corrosion during the preceding five years.

That represented more than $3 billion annually during the period studied.

Among motorists living in winter-climate regions, 15% reported at least one repair caused by road salt or other de-icing chemicals.

For drivers who needed such work, AAA estimated an average cost of $490 per repair.

These are historical figures. They cannot tell us what American motorists are paying in 2026.

Yet they show that corrosion creates costs beyond the ordinary maintenance associated with mileage.

A driver may carefully budget for servicing and replacement tyres. Rust damage can still develop out of sight, especially where road salt repeatedly reaches vulnerable parts of the vehicle.

Some repairs remain manageable. Others involve components whose failure could threaten safety.

The difference matters more than the amount of rust visible on the body.

Source: AAA Road De-Icers and Rust Damage Fact Sheet, 2017

Repairing an Old Car Makes Financial Sense Until Safety Changes the Calculation

In my earlier article, I examined why spending $2,000 on an ageing car might make better financial sense than buying another vehicle.

Suppose a repair keeps a dependable car running for two additional years.

The owner avoids a new loan and may save considerably more than the repair costs. That is one reason people keep older vehicles.

Corrosion can undermine the calculation.

A mechanic might discover heavy rust around a suspension mounting point. Repairing the damage may require specialist structural work rather than replacement of an ordinary worn component.

The owner then needs to consider whether the repair can restore the vehicle to a safe condition.

A professional inspection becomes more important than the vehicle’s apparent mechanical reliability.

The car may still start immediately and drive normally, yet a serious weakness could remain beneath it.

For someone who has avoided a monthly car payment for years, the prospect of replacing such a vehicle can be financially painful.

The Canadian reader who contacted me had reached that decision. His car was running well, but its condition had made replacement necessary in his judgment.

Preventing Rust Costs Money Too

Car owners in Quebec have several ways to slow corrosion.

CAA-Quebec updated its rust-proofing guidance in July 2026. It explains that protective treatments can help preserve metal exposed to salt and moisture, although the result depends on proper application.

Liquid-oil treatments commonly cost between C$100 and C$175. They generally require annual renewal.

Some longer-lasting treatments cost between C$400 and C$700, depending on the product and vehicle.

Those are Canadian prices, and the different treatments do not provide identical protection or require the same maintenance schedule.

The choice creates another financial calculation for owners who intend to keep their vehicles for many years.

Regular washing also helps remove accumulated salt. Underbody cleaning is especially useful because corrosion often begins beyond ordinary view.

CAA-Quebec advises owners to protect exposed metal and inspect damaged coatings before rust spreads.

Even a newer vehicle is not immune.

There is a less obvious problem too. Quebec’s automobile insurance authority warns that parking a salt-covered vehicle in a heated garage can accelerate corrosion.

Warmer conditions may keep moisture active against metal surfaces, particularly when salt remains on the vehicle.

An owner who wants to protect a car during winter may therefore need to think about how it is stored as well as how it is driven.

Source: CAA-Quebec, July 31, 2026

For practical winter maintenance advice, read How to Protect Your Car From Road Salt This Winter.

Geography May Help Explain Why Some Cars Last Longer

An American car’s age also reflects where it has spent its life.

In 2019, the U.S. Department of Energy reported that light vehicles in western states averaged 12.4 years old. Those in the Northeast averaged 10.9 years.

The difference was substantial.

But the figures do not establish how much road salt contributed to it. Local vehicle preferences and other economic factors also influence fleet age.

Some western areas have severe winters, while parts of the Northeast experience very different driving conditions from one another.

The regional averages cannot settle the question by themselves.

They do, however, remind us that the national figure of 12.94 years conceals very different ownership experiences.

A car may reach twenty years of service in a comparatively dry region. Another may need expensive corrosion repairs much earlier.

Vehicle age alone cannot explain either outcome.

Source: U.S. Department of Energy, August 19, 2019

Why Keeping an Old Car Is Becoming Harder for Some Families

The broader American car market creates another difficulty.

Owners are trying to extend the lives of their vehicles partly because replacement prices remain high.

A family that discovers severe rust cannot always postpone the decision until prices improve.

The car may be needed for work, while the household may already be managing other regular expenses.

A sound engine offers little financial relief if a mechanic finds that the vehicle’s structure is no longer safe.

The family must consider a replacement even when the household budget would benefit from keeping the existing car.

Some owners have the money to make that choice comfortably. Others may need to finance a used vehicle with an uncertain maintenance history.

The problem is not simply that cars have become expensive.

A household’s ability to avoid an expensive purchase can depend on the climate in which it drives.

The Car That Still Runs

I keep thinking about the Canadian reader.

He replaced a vehicle that had apparently done its mechanical job well. Winter salt had damaged something the engine’s condition could not tell him about.

His experience complicates the advice to keep a car for as long as possible.

That advice makes financial sense only while the vehicle remains safe.

A driver can maintain the engine carefully and avoid unnecessary replacement costs, yet years of corrosion may eventually force a decision.

The mechanic may turn the key and hear the engine start without difficulty.

The owner still has to decide whether it is worth repairing the metal underneath.

And if the vehicle is no longer safe, the next question is how to pay for another one.

Sources and further reading

Related reading: Why Americans Are Keeping Their Old Cars Instead of Buying New Ones.

Reporting note: The opening draws on a public reader comment about replacing a vehicle because of corrosion. The account is not a representative survey of Canadian drivers.

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