johnwb

Looks like corrosion on the outside of the plastic.
Anyone know what it is, how it got there or how to get rid of it?

CBnAT

It looks more like they lost the seal and have condensation inside to me. Can you feel it on the outside?

johnwb

I can feel it on the outside. It feels a little rough.

CBnAT

Is it possible some of your detailing products are corrosive to the surface of the lights?

number9ine

Did you have someone detail the car recently? It looks like it could be wax or compound residue.

Barring that, the UV protectant coat could be fading, but unless there was some other human factor to blame that would take years of bleaching in the sun.

I'd get some PlastX and polish it, just be careful not to let too much static build up if your 997 is an early '05. Ask how I know

PHDX2

Once corrected, consider applying headlight protection film, like the following:

http://www.xpel.com/products/headlight_protection.asp

Works great!

Fahrer

It looks like crazing. Headlamp lenses are made from polycarbonate (PC). PC has great optical and impact properties and is specified for the front because it is less likely to shatter which is important for minimizing pedestrian injuries in collisions ( acrylics are generally specified for tail lamps). The downside of PC is that it yellows over time and has poor chemical resisitance. Isopropanol will destroy PC in seconds. PC normally is "hard coated". That is, a protective coating is applied to increase resistance to chemicals and UV. If you polish the headlamp lenses you will remove/damage the coating. It is also possible that the lenses were improperly produced. It appears that there are "rainbow" colors in the lenses which indicates to me that the lenses were attacked ( chemically) a bit. If your car was detailed, it is possible that this could have damaged the lenses if they were polished at those edges.

schwartzwest

Macguires and a number of other companies make plastic cleaning and polishing products, which do a pretty good job of clearing up plastic headlights. If it s in pretty poor condition, you may have to wet sand first with fine grit sandpaper working towards plastic polish and cleaner as the last steps. Someone on one of the forums had posted about this process, showing a side-by-side comparison when he was finished one and the results were amazing. It may have been a 996 headlight, but I can't for the life of me find the post or even remember which forum it was on.

YA911Fan

Does the coating prevent isopropyl alcohol from damaging the PC or does the alcohol remove the coating?

I'd been regarding isopropyl alcohol as a benign cleaning fluid...

Minok

Wondering if its abrasion of the surface or if its some sort of buildup like wax/pollen/etc that can be removed.

Fahrer

Isopropy alcohol can be very aggressive. I am not sure about the coating but it severely attacks many materials. It may take a lot of time and exposure to damage the coating. Amorphous (transparent) plastics are particularly vulnerable. The contact time for damage of transparent plastics can be measured in seconds! Put some isopropyl alcohol in a cheap ( disposable ) transparent polystyrene cup and swirl it around. It will craze, stress crack and embrittle before your eyes in several seconds. FYI, I have been in the engineering plastics business for about 30 years ( not bragging, just sharing). I do not know everything but the very poor chemical resistance of PC is well known in the industry. It does offer other key properties that are very useful ( impact, temperature, clarity).

By the way, this why we do not see wipers on headlights anymore. The wipers would abraid the protective coating and accelerate the destruction of the unprotected PC.

tpenta

I have the same thing on the one headlight and it is more on the center of the cover. It is some sort of a surface damage and I've tried some safe-for-plastics polish and it didn't do anything. Unfortunately, the car was like that when I got it so I don't know what caused it. But I can certainly buy the chemical damage explanation.

I haven't worried too much about it but may try to fix it at some point. I'll be taking my car in for some rock chip work in a couple of weeks and will ask the shop what they recommend and inform the group.

Good luck.

-T

Palmbeacher

I'm as willing as the next guy to DIY to save money most times, but when the headlights on my '03 M-B got looking ratty, I had a guy from the Headlight Doctor franchise (same guy who goes to all the dealerships around here) come to my office and do them in the parking lot. They sand them, polish, and then clearcoat them with some acrylic sealant. Cost me $150 ($50 less than the dealer charges for the same guy). To buy a restoration kit (not just polish) would've been something like $50, so for $100 more I had a pro do it (perfectly I might add), and it's warranteed for five years.

LlBr

From personal experience I know you can get the gloss back by DIY polishing. Find and buy a polishing kit with all the papers and compounds and instructions. You must "go thru the grits" (abrasive to "infinitely" fine sandpapers) or you'll waste your time; you can't "polish" deep scratches and blemishes, you must remove them by serious abrasion. IOW, the first abrasive will "ruin" the gloss, will turn it into frosted plastic, subsequent grits will bring the crystal clear plastic back.

JohnnyBahamas

If it is rough to the touch, then I'd bet that's clear coat over-spray.

More proof would be if it was in or near a body shop at some point in its life.

How to get it off? Well, on paint over spray has to be buffed off with the appropriate 'cut' polish and an orbital or rotary wheel.

On plastics? I'd call the, or a, body shop and ask.