# How to Clean Inside Lens of Headlight



## CWJ (Aug 24, 2010)

Hi Chaps

I seem to have got a bit of water on the inside of my headlights at some stage :x and was wondering if anyone knows to how to open them such that I can clean the resultant water marks off the inside of the lens? I have taken the four clips off but this does not seem to release the lens from the backing.

Cheers for any help

Carl


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## Maila (May 4, 2008)

If you take out, you will see a few rubber covers. Don't forget to loose all bolts which holds headlight! One is under fender.

Guess that best is to left if opened to let it dry naturally and for sure after some time, when the headlight will look waterless, use hairdryer.


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## ScoobyTT (Aug 24, 2009)

I don't think it's possible to get to the inside surface of the lens covering, so if you've got dried water marks I think you're stuck with them :?


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## CWJ (Aug 24, 2010)

Thanks Maila but the water has already dried and left marks. I have removed the light from the car but removing the rubber lugs does not give you access to the inner side of the lens.

Any further advice?


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## brittan (May 18, 2007)

I had that on my last TT but the lights dried ok by driving around with the lights on and the rubber caps off.

If you have the clips off then obviously you have the lights out. I think that the lens is also glued on. You could try using a blade of some sort to separate them but some risk of damage to the unit and they are not cheap.

The lights are open vented and you should notice a small funnel shaped connector with hose attached at the bottom of the light aperture.

Sorry, don't know any simple way to get at the marks - cloth on a stick??


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## CWJ (Aug 24, 2010)

Cheers everyone. Maybe its a sign to upgrade to xenons!!


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## steeve (Jul 8, 2010)

If you split the lens from the housing youre going to have to bond it all together again, all a bit messy, the reflectors are difficult if not nigh on impossible to clean. You ought to get a small diameter piece of dowel, and make up a bigger version of a cotton bud. Poke that through the bulb hole and with a bit of meths on the padding carefully clean the inside of the glass.
Other than that buy a new one. Make sure the rubber bulb covers are properly fitted and that should make sure you dont get any water in them again. Just one tip, leave the cover off and have the light on for a while to make sure the air that's in the light is dry or you could get condensation if the air is damp. Or you can carefully use a hairdryer.


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## BLinky (Jul 3, 2009)

how did you get water in there??


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## Maila (May 4, 2008)

What suggest steve is only solution I guess. 
FYI: Water in halogen headlight is usual to many cars. Had replaced 2 sets (even rear lights) on my Nissan Almera in past.
It is caused by high temperature and humidity in air, which is concentrating on hot parts. Every headlight has ventilation holes. So is possible to get water from outside air even if headlights are sealed properly with every cover.


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## talk-torque (Apr 30, 2008)

I occaisionally get condensation, like when I wash the car soon after a drive. The hot engine drive any moisture against the glass - not too bothered about this.

What annoys me is the amount of dust inside the light units, visible with the lights on. Why is the assembly process not arranged to eliminat this? No effect on light output, but looks poo. My wife's Polo doesn't have this!


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## steeve (Jul 8, 2010)

Maila said:


> What suggest steve is only solution I guess.
> FYI: Water in halogen headlight is usual to many cars. Had replaced 2 sets (even rear lights) on my Nissan Almera in past.
> It is caused by high temperature and humidity in air, which is concentrating on hot parts. Every headlight has ventilation holes. So is possible to get water from outside air even if headlights are sealed properly with every cover.


The light unit should be sealed, the only holes being where the bulbs fit. The light unit has an IP rating.
Condensation and particularly water is a sign you have a leak usually between the rear housing and the glass, or the seal on the back has not been fitted correctly. But it is important to allow any moisture in the air contained in the lamp to evaporate.

Electrical equipment was my responsibility for a vehicle maker. Believe me if we had holes in the light units they would all have gone straight back.


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## brittan (May 18, 2007)

As I posted above the light units are open vented via small hoses that terminate behind the grille.

Even the foglights are open vented and if you drive through deep(ish) flood water they get a bit more than condensation in them. :roll:


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## BLinky (Jul 3, 2009)

i thought the Unit is sealed?


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## CWJ (Aug 24, 2010)

@ Blinky: Condensation mate. Evil stuff!! :evil:


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## TT-driver (Sep 14, 2010)

BLinky said:


> i thought the Unit is sealed?


yeah sealed enough to keep the moisture in...not out. Mine tend to fog up a bit in cold moist weather. And I've got a dead little spider in there as well.


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## steeve (Jul 8, 2010)

BLinky said:


> i thought the Unit is sealed?


They are.

The high reflectance finish of the reflectors are produced by vacuum metallising of almost pure aluminium, as we all know aluminium oxidises quite quickly. The effect of moisture and heat inside the headlight will result in considerable degredation of the reflective surface. So its quite important that the environment inside the light to be clean and dry. To suggest that you allow water to run through the light by having holes in it is barking.

Some light manufacturers claim an IPX7 rating for their units.


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## talk-torque (Apr 30, 2008)

steeve said:


> BLinky said:
> 
> 
> > i thought the Unit is sealed?
> ...


As said further above, the TT units are not sealed. There is a vent thingy at the bottom of them which allows them to breath. Check it out. Water running through is overstating it a little! Prove it yourself by pressing the rubber cover over the high beam bulb position. No resistance = no pressure = no seal.


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## BLinky (Jul 3, 2009)

I think i'm going to stop driving though giant puddles at speed for fun then


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## talk-torque (Apr 30, 2008)

BLinky said:


> I think i'm going to stop driving though giant puddles at speed for fun then


Shouldn't cause a problem, BLinky. The breather thingy is designed to keep water out, so if it floats your boat..........


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## brittan (May 18, 2007)

For info here's a picture of the vent I mentioned above. 
The RH arrow indicates the funnel shaped connector that mates with a right-angled adaptor on the underside of the headlight unit. 
The LH arrow indicates the vent tube that ends, open-ended, tucked behind and towards the centre of the aluminium bumper bar.
For orientation, slightly above and to the left of the funnel connector is the inner securing bolt for the headlight unit.

However none of this has been of much help to the OP on how to get rid of the water marks.


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## Digi (Oct 20, 2009)

I think this problem is/was a recall issue as my dealer recalled my car for this even though I never had problem.


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## BLinky (Jul 3, 2009)

Digi said:


> I think this problem is/was a recall issue as my dealer recalled my car for this even though I never had problem.


you sure it was for this and not:

trim

or

DSG reflash?


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## talk-torque (Apr 30, 2008)

brittan said:


> For info here's a picture of the vent I mentioned above.
> The RH arrow indicates the funnel shaped connector that mates with a right-angled adaptor on the underside of the headlight unit.
> The LH arrow indicates the vent tube that ends, open-ended, tucked behind and towards the centre of the aluminium bumper bar.
> For orientation, slightly above and to the left of the funnel connector is the inner securing bolt for the headlight unit.
> ...


brittan has shown the Xenon version. The poor man's equivalent is a bulb shaped soft plastic moulding attached to the base of the reflector unit, just behind the glass.


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## steeve (Jul 8, 2010)

I bow to your superior knowledge of TT's, I was wrong and I humbly apologise...     [smiley=bigcry.gif]

The vehicle maker that I worked for (not cars) would rather have put wasps up their bottom than use any light that was not environmentaly sealed. Our vehicles have a much harder and tougher life than passenger cars.


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## brittan (May 18, 2007)

Nice to know I'm not barking :wink:

What vehicle maker? Commercial? Military?


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