CE750

I seem to recall that the Headlight lens on the W211 (or maybe other MB's) is coated with something.. either to protect it from hazing, or maybe for another reason.. Does anyone know if this is true, and if so, what? Or maybe can they provide me a link to the info?

Thanks...

LukeM

I have 00 e430 sport w/HIDs and was told by MB tech @1800 for merc that it was coated and that Rainx was not recommended. Don't recall what he called the coating.

CE750

I wish I could find some data on this coating.. I've got an insurance claim, and I need to make sure they don't "Buff of the scratch" rather than replace the lens.

lars

Plastic headlight lenses usually have a silicon-based coating to prevent UV yellowing and cloudiness. I don't know about yours specifically. Buffing would remove it.

redcoupe

You can remove the haze or simple scratchs with "clear platic cleaner". There is a kit probabley sold at your local auto parts store that will clean your headlights. Or MB sells "clear platic cleaner" for 129 soft top windows that will do the samething.

CE750

Ok, so that implies no coating, just plastic.. that's something I can live with then.

thanks

LukeM

What implies no coating? That MB sells something for plastic windows?

CE750

red coupe just said that MB sells a polish to remove scratches from your headlights.. the only way to remove a scratch is to remove material.. so I can't see how the two are mutually inclusive.. a coating, and a MB sold polish..

lars

What he said was that MB sells a plastic cleaner for the windows in soft tops. MB also sells car polish, but you wouldn't want to use it to shine up your dashboard.

If you really want to polish out the scratches, go ahead. Other people do. But that's not what you asked at the start of the thread.

CE750

I see, I didn't catch that.. I'm not set on it, I'm much prefer a new light, but as this is a $1000 part, they're fighting me tooth and nail.. and the scratch is very topical (almost a scuff)..

I need some kind of supporting evidence that there is indeed a layer on the lens. To make matters worse, the Shop Foreman at Schumacher Auto in Scottsdale said that they are ordinary polycarbonate plastic lenses and no coating is applied.. this isn't helping my case at all.

LukeM

redcoupe said this: "Or MB sells "clear platic cleaner" for 129 soft top windows that will do the samething."

lars

Try these.

Over time, the front lens can deteriorate. It can become pitted due to abrasion of road sand and pebbles. It can become cracked, admitting water into the headlamp. "Plastic" (polycarbonate), can become cloudy and discolored, turning yellowish. This is due to oxidation of the painted-on lens hardcoat by ultraviolet light from the sun and the headlamp bulbs. If it is minor, it can be polished out using a reputable brand of a car polish that is intended for restoring the shine to chalked paint. In more advanced stages, the deterioration extends through the actual plastic material, rendering the headlamp useless and necessitating complete replacement. Sanding or aggressively polishing the lenses can buy a small amount of time, but doing so removes the protective coating from the lens, which when so stripped will deteriorate faster and more severely.
Source: Quickseek

For technical and stylistic reasons, more and more vehicles are being fitted with plastic cover lenses. Hella is one of the world’s leading manufacturers in this area, too. Plastic cover lenses are manufactured under extremely strict clean room conditions, similar to the conditions for microchip production. In contrast to the manufacturing of glass, only absolutely pure basic materials are used. This is the reason for the higher brilliance and value in comparison to glass lenses. The advantages of the material are obvious: Plastic is around 2/3 lighter than glass – a specially developed hard coating protects the lenses from damage through stones and scratches.
Source: Hella

There is the suggestion here that minor blemishes in a plastic lens can be polished out. It doesn't actually say that polishing will leave the UV coating intact, but it does suggest you should not sand or polish aggressively. If your problem is more in the nature of a scuff than a deeper scratch, the polishing could be OK. I can't suggest to you where the dividing line is. As I said, other people polish out scratches and the reps you deal with may think that's standard practice. Good luck.

DChan415

All headlights and tail lights have a UV protection coating. It does fade over time or if removed by buffing. The best way to restore the shine is to polish the plastic, then coat it with car wax. The wax will fade over time and will have to be reapplied just like on your paint.

CE750

Lars and DChan. thanks..

I also noticed a series of vertical lines in the lens that look to be on the outside which would also be polished off..

Looks to me like they're have no choice but replace it.

lars

For greater clarity (sorry 'bout that) you would not expect to find a coating on a real glass lens.

I don't know the thickness of the coating on plastic lenses, but it will probably be less than a couple of hundred micrometres. This is in the same range as the thickness of a human hair, so if you were to polish off more than that, I think the coating would be gone.

Although I know more about lighting than most folk, I'm not an expert. I sent your problem out to a friend who is an automotive lighting engineer, and hope to post his advice if you can wait till next week.

CE750

I very much appreciate it.. If I can get in touch with him via email and get something from an "Expert" to back my claim that would seal it.

I'll provide my email to you if you wish via PM.

lars

OK, here's the word from my friend.

"Polycarbonate headlight lenses are all coated. Polishing out the scratches would be a bad idea. If it was my car I wouldn't do it. If you polish out the scuff the polished area will turn yellow and the rest of the hard coat will start flaking off. Yellowing could occur in months, depending on where in the US he lives and the amount of sun the car gets. The polished area will scratch easily. A rock or a little pebble will make a ding in the lens."

My friend recently ran the R&D program for a major automotive lighting manufacturer. He has patents in this field and is a member of the EU's vehicle lighting standards committee.

Hope that helps you.

LukeM

Does your friend have knowledge as to whether RainX would have a negative effect on the coating w/HIDs?

CE750

Lars, thanks.. I emailed this thread to the necessary people, and it appears now that we're replacing the light.

Also, I too would be interested to see if Zaino, or Rain-x can effect this coating.. thanks mate!

lars

My opinion: RainX should not damage the coating. The hard coat has been flowed onto the lens and cured by UV or heat. Once it's cured it should be pretty stable.

However, some people think RainX leaves a visible haze on windshields and a haze is on a headlight lens is not helpful, especially if you have bixenon. One of the reasons MB makes us buy headlight washers with bixenons is to minimise the glare for approaching drivers caused by road film on the lens. I'd stay away from carnauba waxes, which might yellow over time and need removing, and anything abrasive. Really, the lens should be fine with just regular washing.

LukeM

RainX will not haze if applied correctly per the instuctions on the container.
In my opinion RainX on the headlights would have a positive effect on sight distance at night in the rain.

The question is was this response "was told by MB tech @1800 for merc that it was coated and that Rainx was not recommended." the correct answer or just a safe answer?.

lars

I'd say it was the correct answer. The difference between RainX being not recommended and not causing damage may be meaningful to some but it's not to me.

Moviela

Mercedes has written the following:

Quote
The headlamp cover plates consist of a plastic material (polycarbonate) and are coated with a clear enamel finish.

Clean plastic cover plate by wiping off with a wet sponge. Do not us abrasive agent or dry rag to prevent scratching the surface.

Do not bring plastic cover plate into contact with solvents or cleaning agents containing solvents because the surface is not absolutely resistant to solvent.

Failure to comply with protective measures could lead to surface damage to the headlamp such as a milky-colored coating, matt areas, and stress fractures.

Unquote

Near as I can tell, RainX has a solvent. Looks like a wet sponge is all you need.

Moviela

Mercedes makes you buy a headlight washer because it is required by US FMVSS 108, and similar regulations in Canada and Europe.

lars

Yes, that's correct, and part of the rationale underlying the regulation is this concern with glare from road film. It raises an interesting point about conversion to HIDs, even using OEM lenses, on cars that are not fitted with headlight washers.

Once a vehicle enters use (i.e. leaves MB's control), the federal regulations assume a somewhat murky status, at least they do in Canada. The only time they might become relevant again is if the car is imported, used, across a border. For a vehicle under 15 years old, here in Canada that would trigger an inspection by an authorised MB dealer, who is required to bring the car back into compliance with the federal regulations before it can be licenced.