Today, I rain-x'd my windows and then thought doing the headlights would be a great idea, too. So I did. Then, I read the "do not use on plastic" warning on the rain-x bottle, and read on the internet that it hazes your headlights. Anyone have any experience with this? Do you think I'm good to just leave it and not do it again -- or should I try to wash the rain-x off the headlights?
I did exactly the same as you about 4 years ago. No problems since. Whether that is different in areas with lots of sun, I couldn't say. But my headlights are as good as ever.
I do my headlights every time I rain-x the windshield. Haven't noted any problems in any of the vehicles I've used it on. When I wax the car (about 1x year), I also hit the headlights too - again no problems. By doing these two things on the vehicles I drive, I've never had a headlight lens get cloudy with age either. I just had the headlight lens cleaned and polished on our 2007 Chev Avalanche. I'm not the primary driver so it's not maintained as well as I would like.
A number of years ago there were issues with using Rain-X on certain motorcycle windshields, which are all plastic of some sort. Caused hazing and cracking. I can't remember which plastics or how to even tell, but I would think it a bad idea even with modern plastics. IIRC, denatured alcohol removed it, but that was from glass. I don't know what denatured alcohol does to plastic headlight covers, if anything. Just wax over the headlight covers.
Wax can form a hazy residue over time. Best thing is a cleaner with uv inhibitor/protection. SCH-I535
Maybe some manufacturers use different plastic formulations in their headlight covers. So maybe some work with the rain-x, and others don't?
I've used Rain-x on every headlight on every car listed in my signature and never had an issue. The 85' Maxima had glass headlights, but after that they were all plastic. Now I don't do it anymore though. I've began using Opticoat 2.0 as permanent paint protection applied the day I buy a new vehicle and that gets applied to the headlights as well now.
