Beware of Autumn Leaves, Your Car's Silent and Potentially Costly Enemy

Street parked cars in the fall
Fallen leaves can cause hundreds of dollars of damage to year leaves if not properly removed and protected against. Ibrahim Boran/Pexels

Shifting seasons means that damage may be coming to your car's paint job, and not just from the usual suspects like road salt and bright sunshine. As the trees shed their autumn colors, leaves may damage your car's exterior.

Leaves find their way into vehicles' hard-to-reach spots —getting caught under wipers, clogging air intakes and drain holes, and jamming up the sunroof. Wet leaves also contain tree sap, which is acidic and can damage the finish on a car's paint so it's best to avoid parking under trees —especially if you're not driving much.

"Anything that's on your paint, you should clean it off right away and sometimes that's not possible if you drive multiple cars and one is parked all the time," said Rob Harper, the director of operations for Ziebart International, an automotive aftermarket company that specializes in refreshing exteriors.

"More often than not, then you want to do something to protect it. And that can be as simple as a car cover," he continued. "But most of our customers end up putting on some kind of paint protection. Whether it's a seasonal wax that lasts a few months or paint sealant that typically lasts about a year, all the way up to our ceramic Z-Gloss, which has a 10 year warranty on it and protects the paint of your car from all of those things."

As leaves decay, they release acids like sap and pollen that harm a vehicle's painted surfaces. Depending on the species of the tree involved - the compounds that leach out of wet leaves damaged unprotected paint in a matter of hours.

The trees to be especially wary of are maples and oaks as they have a tendency to have a very high acid content. However the most damaging tree to be near your car is not one with leaves but rather a pine tree. The needles of the pine tree are a year round problem; they have the highest acid content.

As leaves fall, they can also scratch your fresh paint job, leaving small micro-abrasions that leave your car susceptible to rust, water damage and more leaves, repeating the cycle.

The metal exterior beneath the paint expands and contracts due to the warm days and cool nights of the season. This warming and cooling causes more acid to be produced which then deteriorates the paint, leaving leaf-shaped stains over the body of your car. When the leaves are wet or rotting, this process is even quicker.

Leaves piling up on your car can also clog your air conditioning systems or exhaust pipes, causing further damage to your vehicle. If the leaves begin to rot while stuck inside your car's parts, they become even more difficult to remove and start to smell.

It is important to remove leaves from your car as quickly as possible, but do this carefully. Experts suggest picking them up with your hands or using a leaf blower on the light setting.

"If you use a broom, to drag these leaves across the car, those can abrade the clear coat a little bit," Harper said.

"Anytime you're putting a texture, even a microscopic texture into the clear coat, it's going to affect the way the sun's light bounces off the paint. ...left unchecked, those little ridges or or valleys, the microscopic valleys can collect contaminants, which lead to further degradation of the picture."

To unclog sunroof drains, use a vacuum to draw out the leaves, rather than an object to scrap it out as you may damage the headliner. Don't forget to pop the hood to clear leaves near the base of the windshield, where the car's heater intake system is. Finish up by giving your car an overall rinse.

If left unchecked the damages done to just the exterior of your vehicle can cost several hundred dollars.

To mitigate the effects of leaves on a car, vehicle owners can have their models detailed or invest in a seasonal waxing. Many detail shops also offer some kind of sealant that will seal the paint for about a year.