Yellowed Modern Plastic Headlights

[jsmithepa]

If Modern plastic headlights yellow because of UV, how come the taillights don't yellow? they are plastics too! don't tell me UV only hits you from the front!

 

[Solandri]

There's a UV-blocking film that's sprayed or wiped on to plastics that will be sitting in the sun a lot. It remains intact on your tail lights. But your headlights get hit by dust, bugs, and small bits of road debris as your car moves forward, and this protective layer gets scrubbed off. At which point they start to yellow.

The better headlight restoration kits include a small vial of UV blocker that you're supposed to wipe onto your restored headlights as a final step.

 

[DSzymborski]

First off, tail lights *can* yellow. Second, it's not just the UV, there's a clear film coat on the headlights and the front headlights are more exposed to most of the other causes that erode that film.

 

[jsmithepa]

LOL it makes sense. Ah modern cars, all plastics, not cheaper.