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Mot - Headlight Moisture


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Hi all,

:question: Does anybody know if having moisture in the headlights is an MOT failure? Not sure how the water is getting into the light either. I can’t see any bad chips on the lens.

Any help gratefully received

Lee

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Not sure about an MOT failure but its a common problem with the Is200's.Its about £100 for a new headlight.You could take the bulbs out and hold a hairdryer in the bulb holes to dry it out but it will just come back again.What i did was drilled a 10mm hole in the back of the light just to let it breath and though it does not stop it from misting it up it does dry out quicker once the car is started i hope this helps you out mate

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Moisture builds up in headlamps when it cannot breathe, usually a headlamp will have two holes in it that are usually covered in a shield or labyrinthe to stop running water getting in.

What I would recommend is to check that the breather holes are clear, if they are then most likely a leak path past the lens through between the interface between the lens and housing, then water will tend to get in during wet conditions but not be able to dry out in time through the breather holes.

If you have had the headlamp lens off to do a mod this would be the most likely cause. Whip the lamp off and run a bead of silicon sealent or mastic around to seal any holes.

If you wish to cut an additional breather hole in the lamp make it as big as possible (for laminar flow of air) but try and do it so any water can't get in.

You can buy Gore tex pads if you are in the industry to stick over the hole and allow it to breath, but i've never seen them available privately.

Hope this helps

Bod: Is that £100 per headlight or for a set of 2. The hardcoat on the lenses of mine is de-laminating and I was looking to replace.

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Not sure about an MOT failure but its a common problem with the Is200's.Its about £100 for a new headlight.You could take the bulbs out and hold a hairdryer in the bulb holes to dry it out but it will just come back again.What i did was drilled a 10mm hole in the back of the light just to let it breath and though it does not stop it from misting it up it does dry out quicker once the car is started i hope this helps you out mate

Thanks mate. That does help. :)

I am in a bit of an odd situation regarding the MOT. Let me explain..... :duh:

I brought the car just a couple of weeks back from my local Nissan dealer. I had to wait a week before I could pick it up, so that it could have its MOT and a service. No problem I said. When I picked it up they said they did not bother with the MOT because it still had its MOT until January 08. I was not happy. :angry: I had paid for the car thinking that I was going to get 12 months ticket.

In their defence they did book it in for an MOT a couple of weeks later (today). Having driven it for a couple of weeks prior to the MOT I was able to make a list of problems, such as inner tyre wear (bad!). I also thought that the headlight having water in would be a problem. All would be sorted through the warranty.

I picked the car up and they had indeed replaced the front tyres under the warranty. But no mention about the lights. I just wanted to know where I stood before getting to angry.

thanks all

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Moisture builds up in headlamps when it cannot breathe, usually a headlamp will have two holes in it that are usually covered in a shield or labyrinthe to stop running water getting in.

What I would recommend is to check that the breather holes are clear, if they are then most likely a leak path past the lens through between the interface between the lens and housing, then water will tend to get in during wet conditions but not be able to dry out in time through the breather holes.

If you have had the headlamp lens off to do a mod this would be the most likely cause. Whip the lamp off and run a bead of silicon sealent or mastic around to seal any holes.

If you wish to cut an additional breather hole in the lamp make it as big as possible (for laminar flow of air) but try and do it so any water can't get in.

You can buy Gore tex pads if you are in the industry to stick over the hole and allow it to breath, but i've never seen them available privately.

Hope this helps

Bod: Is that £100 per headlight or for a set of 2. The hardcoat on the lenses of mine is de-laminating and I was looking to replace.

I suppose if it a simple job to repair myself, then I dont need to go accusing anybody of a dodgy MOT. Thanks for the advice.

If I do decide to buy new headlights am i right in thinking that they changed the design on the newer models. If so are they a straight swap? My car is on a V plate.

Thanks all

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Hello, I work at a garage and just had a word with our mot tester it proberly would fail an mot because it would distort the light pattern. But it all depends on where the condesation is and how bad.

Steve.

Thanks Steve. Ill put a picture up later, just for a matter of interest.

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Also what we do for quick fix is put a blanket over the headlamp with them on full beam for about 10-15mins this will get it through an mot plus should keep them clear.

thats actually a really clever solution, and problem solving method. If, after trying the 'blanket' method, the lamps fog up again then the breather holes are blocked. IF they only fog up again when it rains then you probably have a leak through the front.

Personally I wouldn't go buying new lamps just for that problem, it should be fixable.

I can't speak for the Lexus but quite a lot of Japanese lights have a small rubber tube that bends 90 degs down, and are just pushed over a tube coming out of the light. The rubber tube contains a plastic 'moss' that lets the light breathe but prevents water getting in. It could be just a simple case that the rubber tube has dropped off.

Either way you have a couple of methods of repairing it.

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