Mystery of the mysted - I mean misted - headlamps

[Bobby Dazzler]

Someone I know well took their car to local MB dealership, and having picked it up they returned home and noticed that one of the headlamps was badly condensated on the inside. Took days to dry out and left inside of the bi-xenons lens cloudy. Told Sales Manager verbally and Service Manager in an email.

Returns to dealer few weeks later, and asks that they don't wash the car given the previous condensation. Pick the car up and the same headlamp is condensated again (80-90% with water droplets) and other side has some mist (30%), and both fog lamps condensated. All interior windows misted too.

Expressed concern immediately to service advisor - service manager in a meeting - and took photos. Followed up with an email. Assured that they didn't wash the car as instructed, and can't see what it has to do with them.

Not happened at any point during 12 months of ownership except these last two visits to dealer. One of the headlamps was replaced only a few weeks ago at a cost of £1000.

Any idea on what might be causing it, and what the best course of action is?

All help appreciated!!

 

[Andy W]

£1000 for one headlamp! Why?

 

[portzy]

I would say theres nothing unusual about the window/s being misted up if the car has been in the workshop for a few hours then brought out into the cold. The relative humidity has been quite high lately and it doesnt take much for it to condense when moving a warm atmosphere (car interior?) to a colder ambient one. If you see what I mean.

The headlamps etc are another matter. They are not completely sealed, they have a small breather hole right at the back of the lense which is designed to allow a free flow of air in and out as the interior of the lens warms and cools. If it was'nt there the unit would pressurise it self etc.

This also allows any condensation to flow away and the pressure to equalise. The problem occurs when the process of condensation is 'forced' i.e. washing the car or moving it from a relatively warm atmosphere to a much cooler one. The condensate formation is quite rapid and the breather set up cannot cope so you can see the effect inside the lens and sooner or later you get water marks.

I would be tempted to check these breather holes for blockages, wherever they happen to be. Somehow I think that they will be hard to get at and even then, MBZ will claim that this phenomana is quite normal per the handbook.

Oh, by the way, my SLK suffers from exactly the same thing but thankfully the water marks are only visible to me if I look very closely.

Portzy.

 

[glojo]

Hi Bobby,
I hope this friend does not live near that huge 'lake' that KLP sometimes has to drive through.

Does the car live in a garage at the owner's home address? I ask this simply because I am trying to understand why it only happens when the car goes to the dealership!

Regards,
John the inquisitive

 

[Bobby Dazzler]

Thanks for the explaination portzy. I wonder if the workshop is very warm then, and the change of temperature is causing it? That said the dealer haven't suggested any other cars are affected by it so maybe the breather holes are obstructed?

glojo - I don't think he's been to KLPs place recently - apparently the Pizza's not been up to much lately!! Keeps it in the open on the driveway at home, and carpark at work.

 

[Bobby Dazzler]

£1000 for one headlamp! Why?

That's what I said too!!

 

[Bobby Dazzler]

Dealer has had the car in today, and it seems there is a seal around the bulb (capsule) that wasn't seated correctly, and had let water in. Been thoroughly dried out apparently.

No explaination as to why it only happened at the dealer though.

They are going to find out if there is any way of cleaning the cloudy mark left on the inside of the lens, but whether they will remains to be seen.

Anyone have any bright ideas about how to get rid of the marks?

 

[Dieselman]

The dealer probably jet washed the engine bay after work on the engine.

 

[glojo]

The dealer probably jet washed the engine bay after work on the engine.

Certainly makes a lot of sense.

John

 

[dagd]

So, is this the headlamp that wasn't replaced or the one that was?

 

[Bobby Dazzler]

The one that wasn't was condensated heavily.

The one that was replaced just had a light mist.

 

[Monique]

I don't know about you but normally, I get kissed before something like that happens to me

Some of you dudes are not very mechanically minded... remove the light assembly (20 minutes), removes lens and spray with white vinegar. Let soak. Rinse and dry thoroughly.

Rebuild the light assembly ensuring you have a good seal on the gaskets. Reinstal the light unit.

Save GBP 1000:bannana:

 

[Bobby Dazzler]

Some of you dudes are not very mechanically minded...

Very true - I am possibly the worst offender, not even washing the cars myself anymore. Not very good with my hands and lazy - not a great combination.

Thanks for the suggestion. When rinsing, won't the water marks re-appear? Also will vinegar be OK on the silver reflective surface inside the headlamp?

 

[Monique]

Yes on both counts. Works great on plastic, Lexan or glass. Use soft cloth to dry... no scratches.

Merry Christmas

 

[portzy]

I don't know about you but normally, I get kissed before something like that happens to me

Some of you dudes are not very mechanically minded... remove the light assembly (20 minutes), removes lens and spray with white vinegar. Let soak. Rinse and dry thoroughly.

Rebuild the light assembly ensuring you have a good seal on the gaskets. Reinstal the light unit.

Save GBP 1000:bannana:

I wish mine were that easy, it seems on the SLK that the first thing they fitted was the headlight units then built everything around them. Major surgery I'm told for me, still, my watermarks are extremely slight and dont bother me that much.

Portzy.

 

[Monique]

If you come to EU on a visit, I promise to fix it in under an hour. Our mate was had big time. The complete lexan unit costs Euro 129. I would ask some very pointed questions of the MB stealer IIWM

 

[Bobby Dazzler]

Cheers Monique.

I wish mine were that easy, it seems on the SLK that the first thing they fitted was the headlight units then built everything around them. Major surgery I'm told for me, still, my watermarks are extremely slight and dont bother me that much.

I think it's a 'bumper off' job on the W203.

 

[A-AvantGarde]

Sure is, bumper off to replace ligts on the W203. Many cars are going this way. You can just about do it without remmoving the bumper (apparently) although it's not worth the hassle, far easier to remove (or get someone else to) the bumper.

 

[Bobby Dazzler]

Dealer has had the car in today, and it seems there is a seal around the bulb (capsule) that wasn't seated correctly, and had let water in. Been thoroughly dried out apparently.

Apparently a faint hint of mist again over the weekend, only in the headlamp that suffered least. Presumably they only dried out the heavily condensated headlamp!! Doh!!

 

[jeremytaylor]

My W211 E320 with Xenons has had slight condensation around the edges of the light unit recently, but not on the bulbs or in front of the bulbs (I say bulbs, but you know what I mean!).

These lights get hot, so it's not entirely surprising!