Look at almost any car more than a few years old and you'll see it: headlights that have gone from crystal clear to a dull, yellowy haze. It ages the whole car, and more importantly, it cuts down how much light actually reaches the road.
So do you restore them or replace them? It depends on what's causing the haze. Here's how to tell, and what each option involves.
Why headlights go cloudy
Modern headlight lenses are made from polycarbonate, a tough plastic that's much lighter and safer than glass. When the car is new, the lens has a clear UV-resistant coating on the outside.
Over time, sunlight breaks that coating down. Road grit, car washes and harsh cleaning products wear it away too. Once the coating goes, the plastic underneath starts to oxidise, and that's the yellow, frosted layer you can see.
That's the most common problem, and it's on the outside of the lens. Some headlights also go cloudy on the inside, which is a different issue.
Does it actually matter?
Yes. A badly clouded lens scatters the light instead of focusing it, so the beam is dimmer and less defined, and oncoming drivers can get more glare. At an MOT, the tester checks the headlight beam and the condition of the lens, and a lens that's damaged badly enough to affect the beam can be a problem.
The quick test: inside or outside?
Run your fingertip across the lens. If it feels rough or slightly chalky, the haze is on the outside, and restoration will usually help.
If the outside feels smooth but the light still looks foggy, or you can see droplets or a misty film behind the lens, the problem is inside the unit. You can't polish that away.
When to restore
Restoration works well when the cloudiness is on the outer surface and the lens isn't cracked. Most kits follow the same steps:
- Mask off the paint around the headlight with masking tape
- Wet sand the lens with progressively finer grades of abrasive paper to remove the oxidised layer
- Polish the lens back to a clear finish
- Seal it with a UV-protective coating
The last step is the one people skip, and it's why some restored headlights go yellow again within a few months. Without a new UV coating, the bare plastic starts oxidising almost straight away.
A good restoration can make a real difference for very little money. But it has limits. It won't fix deep pitting, cracks, damage inside the headlight, or a lens that's been sanded too many times before.
When to replace
Replacement is the better choice when:
- The lens is cracked or chipped
- There's condensation or water inside that won't clear
- The reflector inside has gone dull, flaky or burnt
- The mounting tabs are broken, so the headlight won't sit straight
- You've already restored it and it's gone cloudy again
- The headlight was damaged in a knock
A new headlight brings back the original beam pattern and a fresh factory coating, so it stays clear for much longer than a restored lens. It also fixes problems a restoration can't touch, like a damaged reflector or a failed seal.
If you have condensation inside the light, check the vent caps and the rear covers first. A missing cap or a cracked housing can let damp in, and replacing the whole unit won't help if the same gap lets water into the new one.
Replace in pairs?
If one headlight is badly damaged and the other is only slightly hazy, a new headlight next to an old one can look mismatched. Many people restore the good side or replace both together so they match. It's your call, but it's worth thinking about before you order.
Fitting a new headlight
On many cars, the headlight is held in with a few bolts that you can reach by opening the bonnet. On others, the front bumper needs to come off first. Have a look at your car before you start, or check a guide for your model.
Once it's fitted, the headlight aim needs checking. A light that points too high will dazzle other drivers, and too low will cut your view of the road. Most garages and MOT stations can set the aim quickly.
Finding the right headlight
Headlights are very specific to the make, model and year, and many cars have several versions depending on trim, such as halogen, xenon or LED. The safest way to get the right one is to match the part number on the back of your old unit, or the OEM number. If you're not sure, send us your VIN and we'll help you find the right one.
We stock thousands of replacement headlights for most popular makes in our lighting range. You can also search for headlights with your make and model.