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Headlights fogging in cold wet weather

TobesEtc

Well-known member
Joined
2 Jun 2014
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1,849
During the recent very cold wet weather I noticed my headlights fogging. I understand that driving the car in such weather is an automatic de-merit from the Illuminati, but I've done worse to it over the holiday season (there are clues).

Anyway, simple enough to dissemble the lights, dry and refit, but how do I stop it happening again? Slight smear of Vaseline on the seals, perhaps? Ideas?
 

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At this time of the year I have my headlights on all the time, just for safety reasons: dark, dull, low sun, bad weather. By using them more, the heat usually evaporates most the moisture out of were ever it got in.
 
The headlight has an air hose connected to remove moist air and any temperature difference between the inside and outside air. This hose is part of the main headlight bucket connector.
If the car is coming out of a warm garage, it will take time to fill the headlight bucket with cold air, and thus remove the reason for fogging.
Condensation of water vapour will always occur on border surfaces between hot and cold air.

Cheers,
Tore
 
I have noticed the same issue from time to time.
Tore any pictures of the tube? I'll google it as well but will make sure I do not add Tobe's vaseline into the search....just in case...
 
Fulla said:
I'll google it as well but will make sure I do not add Tobe's vaseline into the search....just in case...

:floor: :floor: :floor:

:thumb:
 
The plastic tube will be clearly visible if you extract the headlight bucket. It is a clear or white tube, about 7mm in diameter.
Cheers,
Tore
 
Fulla said:
I have noticed the same issue from time to time.
Tore any pictures of the tube? I'll google it as well but will make sure I do not add Tobe's vaseline into the search....just in case...

:hand: Incognito, always incognito...
 
The tubes are meant to have a small black wedge shaped piece of plastic where they exit underneath the car. Mine are missing [sorry....] and I get reminded every time I have the car serviced [OPC Brooklands are thorough!].
 
Recently had my headlight pods apart when fitting the Morimoto bi-Xenon projectors . I put new seals in between the lens and body, also noticed a vent hole in the base of the pod which I will be covering with a Gortex plaster as fitted to some headlight pods. So far no misting since I replaced the seals.
part no. 993 631 907 00
 
Is Gore tex fabric directional? I seem to remember the marketing bumf that came with my jacket indicating that it kept rain out but let sweat out too. This could dictate which way round to apply the plaster?
 
Covering the light ventilation holes is a huge mistake.
The reason for fogging is not that moist air is coming into the light housing, but the temperature difference between the in- and outside air.
If you move the car from a warm environment out in the cold, you will need the ventilation holes to get rid of the warmer air inside the light to avoid fogging.

Cheers,
Tore
 

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