Cracking headlight plastic

[dr.bmw]

Hey guys
noticed tiny little cracks in both my front headlights, numerous almost horisontal cracks almost like multiple stone chips. I suspect its from heating/cooling of the plastic from running the lights on all the time
anyone else has the same problem?
Cheers

[Guran]

If you suspect it's caused by the xenons, you should take it to your dealer for a warranty repair.

[SimonB]

I have the xenons and use the daytime running lights and, for a change, don't see the problem.

[TimMc]

Originally Posted by Guran

If you suspect it's caused by the xenons, you should take it to your dealer for a warranty repair.

As I understand it... Xenons should be cooler than halogens as much more of their 35W power goes to creating light rather than heat. Halogens 55/60W bulbs are less efficient and hotter.

[dr.bmw]

Dunno, the dude who owned the car for 4 months before I bought it put aftermarket blue/white headlights in them. Not even sure of the brand but they whiter and brighter than the stock yellowish ones

[Jeef Beef]

Originally Posted by dr.bmw

Dunno, the dude who owned the car for 4 months before I bought it put aftermarket blue/white headlights in them. Not even sure of the brand but they whiter and brighter than the stock yellowish ones

Well then it sounds like you have halogen bulbs and not xenons. The previous owner might have 'upgraded' the stock bulbs to the ones that give it the blue 'xenon' effect.

Not a problem within itself (other than the fact that they usually emit less light than the standard yellowish white) but if he went for some el cheapo ones off the internet, then the glass on the bulb might not have a UV filter. That unfiltered light high in UV might be what's causing damage to the headlight plastic. If you want to claim under warranty, I suggest you replace them with stock bulbs before you take it into the dealer.

[MickyD]

I think the beefmeister has nailed it.... no UV cut will kill the lens covers VERY quickly.

[05C4R]

lens covers should have uv protection in them, there in the sun all day, or am i thinking of something else...

[Jeef Beef]

Originally Posted by MickyD

I think the beefmeister has nailed it.... no UV cut will kill the lens covers VERY quickly.

Haha beefmeister. Love it.

Originally Posted by beemer

lens covers should have uv protection in them, there in the sun all day, or am i thinking of something else...

Yep you'd be right, the plastic on the covers would be designed to withstand UV from the sun. However, most of the harm has already been filtered by the ozone layer.

A high power halogen bulb within 5cm emits many many times more UV than is possible to receive from the sun. That's why the glass on the bulb (which is immune to the deteriorating effects of UV unlike plastic) should contain a filter in order to protect the lens cover.

OP, get those bulbs out before they do further damage! If the cracks you are talking about are hairline width, then it definitely sounds like UV deterioration.

[dr.bmw]

bummer
i suspected as much

[qship]

Wouldn't putting in high drain halogens throw a code. I thought the halogens ran different voltages and draw than xenon. Any sparkies want to comment?

[Jeef Beef]

Originally Posted by qship

Wouldn't putting in high drain halogens throw a code. I thought the halogens ran different voltages and draw than xenon. Any sparkies want to comment?

dr.bmw does not have the xenon option for his 125i, so his headlights are halogen. As long as the replacement halogens are also 55W/12V, no code will be thrown. Blue-look halogens usually have a filament that burns at a higher temperature and/or a blue filter on the glass.

[qship]

Thanks for the info.