After getting the girl back from her spa week it looks like the spidering around the edges of the headlight housing wasn’t superficial and could not polish out.
It’s now covered in protection film but I still don’t like the look of it.
1. Is this a common issue with the headlight housing?
2. How easy is it to swap out the housing while retaining bulbs, xenon ballast etc?

 

1. Yes very common. All plastic headlights will eventually get to this state. Depending on the amount of UV and also heat exposure, some quicker than others. They're tiny cracks through the whole body of the outer lens. Polishing therefore is futile other than for the outer surface.
2. Id'e say its the same for the x150 as my x202 S-Type R that the outer lenses are not available to buy as a separate item.... Therefore unless you want to buy new the only choice is to stock up on the best used ones around you can find to keep as spares if you intend to keep the vehicle long term. Fortunately for us S-Type owners there's a bigger used headlight market as the standard S-Type quartz lights have the same outer lens. I have seen some second hand outer lenses for sale over the years.
There's a bit of skill involved in removing the outer plastic lens but very doable.

 

It's the clearcoat that cracks, you can restore them by sanding them down and a new layer of clearcoat.
Google it!:-)

 

Stiggy,

Can you post some close-up shots of the problem? I think that would help with diagnosis. Thanks.

 

Finally got round to taking some pictures of the headlight housing issue.






My detailer said they tried to polish it, but no joy. The lamps are now covered with paint protection film to the edges so hopefully it doesn’t spread.
They just don’t look great.

 

Try a body shop. They can get a bit more aggressive in removing layers of plastic and then spray them with new UV clearcoat, then PPF. Should give you 5+ years.

 

Just thought it’s strange that it’s just the edges of the lenses. I’ve seen dulling on lenses before but not like this and not from the edge on in. The majority of the headlight lenses on both sides are crystal clear otherwise.
If it’s just the clear coat on them, I’ll take to a body shop and have them move the housing and do a restore and recover in PPF again. Sucks that I just had the whole front covered a couple weeks ago.

 

Before the PPF went on, did you feel that the surface of the lens was rough? That would indicate a problem with the clear coat. If the lens felt smooth, I'm guessing it's inside the lens.

 

You'll find that the UV rays have now 'cooked' these lenses. They will get worse with age. Buy new or look for a good used pair now before they become impossible or ridiculously expensive as the rarity factor increases.
The angle/design of the lights can make the edges more susceptible to UV rays with the beautiful XKR a prime example.
If the car was always in a garage or you were in say Northern Europe or Alaska the problem would not be as immediate.
The 'stress cracks' caused by Australia's harsh sun are now all the way through my lenses as seems to appear on yours. All I could do was polish for the purpose of just a re coating and live with the stress crack look until I replace the lenses from a good used pair I have. But I'm not in so much of a hurry as I know it will happen again to this spare pair I have...
Enough UV rays on any modern plastic headlight and the same fate awaits.

 

The result of mine cleared then baked . I prepped the surface with 1500grit wet (mini orbital) then got the guys to hit them in the spray booth Not hard to remove disconnect the harness, water jet tubing , release the front bar from the top x3 plastic plugs / 10mm bolts. When un bolting the headlight there also is a bolt in the inner wheel well .

 

Yeah the edge felt rough, although I couldn't really tell how deep those lines were to determine if it was just on the surface.
With prelim searching, new replacement housing are $2500 a piece!!
Are there any changes to the headlight housing from 2007 onwards? Sourcing these suckers seem to be quite difficult.

 

I've seen on the porsche forums that some of the Macans have had similar problems. Although not found that any of those owners have been able to polish the lenses they've just had the dealers replace the housings.
Unfortunately I don't have that luxury...not for 5k for the pair in any case.

 

They were redesigned for 2012 onward. This is not clouding or hazing so a standard polish will do nothing. It is possible the cracks are too deep but the body shop should be able to determine. I have seen these on eBay many times for $400-$600 apiece, have you had a look? I see 2 right now for $800 OBO and recently sold ones for $400-$600.

 

To change just the lenses any 7-11 housing would fit and wouldn't need to be Adaptive, which are a premium price. Just bake the lenses off and switch those.

 

There are 2 versions, 2007-2011 and 2012-2015

 

Is it possible to just sand down slightly and re-apply a clearcoat?

 

alright i'll bite. generally speaking, one shouldn't want to waste time/effort here. plastic headlight covers (they're technically not "lenses") come from the factory with a thin layer of UV coating impregnated into the outer or top surface. this coating fails all on its own, after which permanent damage is done to the lower layers of plastic by the sun, and you get fogging (whether or not you get a color change). this is unavoidable.

however, the minute you even begin to polish your covers, you are destroying whatever is left of this coating, and if you're involving sanding as well, some of the plastic underneath. you will enhance the rate of this one-time natural process.

now supposing it's already happened, why not try anyway? true. and you might do an excellent job at this. i have paid for a $50 or so kit myself and spent a couple hours teaching myself how to do it (different car). but, in the end, even with all that work, and a new (expensive!) surface coating that offers UV protection, you're simply not manufacturing it the same as the factory is. if the factory covers lasted you 5-10 years, great, but the DIY equivalent isn't going to make it that long. so you'll want to decide whether to try based on reasonable expectations, is all. for the average DIY effort, you should expect more fogging and total failure within six months.

won't tell you "no, never do this, ever," because if you're like me you'll want to try it out at cost merely for the experience. and i bet there's better UV coatings now than there were ten years ago.

 

I've done the removal, sanding, and clearing with a 2K UV protectant clear coat on a former car of mine. It was an 05 Audi A8L W12. After 4 years they still looked good when I sold the car. Honestly if you owned one of those cars, removing headlights every few years would be considered Zen relaxation, and you'll have that front bumper off REGULARLY. I think it was Eastwood or something.

 

Acetone, lacquer thinners, or MEK, if it comes in contact with polycarbonate lenses, WILL cause severe crazing.
This is different than UV caused cloudiness from too much time in the sun.
The UV problem can be corrected well, with a headlamp restoration kit, like 3M, or Autoglym, or others.
Any chance you were cleaning your hood/bonnet with a rag that had one of these chemicals on it, and the rag touched the lens.
In my experience, you cannot go deep enough to remove the cracks.
Bob

 

Those kits and other similar solutions and services DO NOT WORK. I had an Infiniti as a daily driver and after just 2 years the headlights began to dull. I took it to a detail shop and for $45 they buffed the lights to a gloss, applied polish and then a "sealer". This lasted for about 30 days. Once the coating is done, there's no coming back UNLESS you do this. About 12 or 13 years ago my 2005 Super V8 headlamps were quite pitted by stone chips. I removed the headlamps, sanded them down with a rotary sander and applied a catalyzed UV clearcoat spray. Not only did they look brand new when done, they continued to do so until I (regrettably) sold the car in 2012.

A few years ago I had a Mercedes GLK with the advanced lighting package (LED DRLs, adaptive bi-HIDs, etc) and within a couple of years the headlamps began to develop those spider cracks. Warranty would not cover as dealer stated it was purely cosmetic caused by neglect so I took them to a local restoration specialist (wheel scuffs, dents, bumpers, calipers, etc) and for $100 they wrapped the car and masked everything off, wet sanded, polished and then finished off with a clear similar to what I did years before and again they lasted for some time before turning the car in.

Interesting to note the 2008 XKR headlamps look brand new even after 12 years and some road course racing.