In Quebec, we dump about 1.5 million tons of salt on the roads every winter. That's massive. Your car drives through that stuff for 5 months a year. And while we worry about rust on the body and underneath the car, we often forget what salt does to your headlights.
What Road Salt Actually Does to Your Headlights
Road salt (sodium chloride and calcium chloride) is abrasive. When it gets sprayed onto your headlights by the wheels of cars in front of you, it acts like very fine sandpaper. Not enough that you'd notice it in a single day, but enough to build up over an entire winter.
The salt wears away the UV-protective coating that the manufacturer applied at the factory. Each winter takes away a little more of that barrier. And once the protection is gone, the polycarbonate is exposed directly to UV rays. The yellowing starts. We explain the whole oxidation process in our article about polycarbonate and headlight yellowing.
There's also a chemical effect. Salt mixed with water creates a saline solution that's slightly corrosive. It builds up on your headlight surface and speeds up the breakdown of the plastic. That whitish film you see on your headlights at the end of winter? That's it.
Abrasives Too: Sand and Gravel
Salt rarely travels alone. Municipalities often mix fine sand or gravel with salt to improve traction. These particles are even more abrasive than the salt itself. They create micro-scratches on your headlight surface that make the plastic more porous and more vulnerable to oxidation.
Throw in the rocks flying on the highway, gravel from parking lots, and general road debris, and your headlights take a real beating during a Quebec winter.
How to Limit the Damage
The first thing is to rinse your headlights regularly during winter. A splash of clean water to remove accumulated salt. You can do this with a garden hose or even a water bottle if you don't have access to a hose. The idea is to not let the salt dry and crust over on the surface for weeks.
That said, avoid rubbing your headlights dry when they're covered in salt. The salt crystals will act like sandpaper and scratch the surface. Rinse first, rub second. Gently.
A ceramic coating applied before winter offers good protection. The ceramic layer creates an extra barrier between the salt and your headlight plastic. We go into detail about this in our article on ceramic coating for headlights.
The Best Time to Get Your Headlights Restored
Spring is the ideal time. Winter just wrapped up, your headlights took a hit, and you've got the whole summer ahead to enjoy the results. Getting your headlights restored in April-May is like getting a check-up after the cold season.
Fall is also a great time. You head into winter with clear headlights and a fresh protective coating, which maximizes your visibility during the darkest months.
Book an appointment at leroidesphares.ca for a restoration with ceramic protection included. We come to you in Montreal and on the South Shore.
