Slight condensation in headlights
- Thread starter Deano3
- Start date
I have same condensation in my led headlights. It does appear to get worse in cold and damp conditions
the lower the temperature of the air, the less moisture it can hold.
Thus the term relative humidity, eg 60% at 20 degrees. might be 70% at 15 degrees. (don't quote that as its just an example and I wont be looking up the actual figures)
Therefore when the tmperatures drop, or you wash the car the temperature of the plastic/glass is cold, which reduces the air temperature to a point where condensation can occur. and so is common this time of year.
(this is why we get condensation on glass in the winter.. colder temps, cold glass, we breath out moisture, we wrap up warm... we put the blowers on leaving a humid high temperature in the car which we then leave to cool resulting in condensation)
turn heaters off towards end of journey and open windows to provide an air change sometimes helps in the morning after. but forget it if you have anything wet on the car, like a coat or the rap you wiped the windscreen with yesterday..
headlight wise: clearly other aspects impact this:
any leaks in the headlight can allow water inside.
how well is the headlight unit sealed? - or what were the conditions like when it was last open?
(if you say headlights are sealed, - how do you change the bulb?)
much like a bathroom increasing the temperature, or introducing air replacement (extractor) is the way to correct.
In the case of headlights, turning them on increases air temperature, which can then appear to remove the condensation. - however when the air temperature drops it can re-form.
Alternative options are:
remove back of light and leave to clear. then replace. - hoping that the relative air humidity is low at the time as this will help.
or open rear of headlight and use a hair dryer. - but if you do this leave the back off for a while to cool, or use cold function on dryer for a while before resealing to remove the warn humid air.
Thus the term relative humidity, eg 60% at 20 degrees. might be 70% at 15 degrees. (don't quote that as its just an example and I wont be looking up the actual figures)
Therefore when the tmperatures drop, or you wash the car the temperature of the plastic/glass is cold, which reduces the air temperature to a point where condensation can occur. and so is common this time of year.
(this is why we get condensation on glass in the winter.. colder temps, cold glass, we breath out moisture, we wrap up warm... we put the blowers on leaving a humid high temperature in the car which we then leave to cool resulting in condensation)
turn heaters off towards end of journey and open windows to provide an air change sometimes helps in the morning after. but forget it if you have anything wet on the car, like a coat or the rap you wiped the windscreen with yesterday..
headlight wise: clearly other aspects impact this:
any leaks in the headlight can allow water inside.
how well is the headlight unit sealed? - or what were the conditions like when it was last open?
(if you say headlights are sealed, - how do you change the bulb?)
much like a bathroom increasing the temperature, or introducing air replacement (extractor) is the way to correct.
In the case of headlights, turning them on increases air temperature, which can then appear to remove the condensation. - however when the air temperature drops it can re-form.
Alternative options are:
remove back of light and leave to clear. then replace. - hoping that the relative air humidity is low at the time as this will help.
or open rear of headlight and use a hair dryer. - but if you do this leave the back off for a while to cool, or use cold function on dryer for a while before resealing to remove the warn humid air.
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Good explanation
All have my mk3's have had condensation in them at some point, think it's also to do with the leds giving off only a fraction of the heat of an incandescent bulb
Page 110 of the manual states:
In cold or damp weather conditions, the headlights, tail lights and turn signals
may mist up inside temporarily. This is normal and in no way effects
the useful life of the vehicle lighting system.
In cold or damp weather conditions, the headlights, tail lights and turn signals
may mist up inside temporarily. This is normal and in no way effects
the useful life of the vehicle lighting system.
I'm sure others have reported issues with snow not clearing (due to melting) from the LED headlights.
I've read on here about some applying RainX on their headlights for that reason....
Headlight units are not totally sealed so with the natural expansion and contraction of the metal, glass etc, air, moist or dry is drawn into the unit. If it's moist and then the arctic blast hits, then condensation occurs as per andycupra's great explanation.
My defunct BMW used to have rubber moulded vents in the headlight unit to allow the air in and out. Expect SEATs just have poor sealed joints .
My defunct BMW used to have rubber moulded vents in the headlight unit to allow the air in and out. Expect SEATs just have poor sealed joints .
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Does anyone know if that actually works? I've got some in my garage, think I'll give it a try and see...
The wax or sealant am using at the time for the paint work also gets put on the lights and works well might give my h2go rain repellent a go on them next time tho
Mark
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its normal, its just physics....
however given its a known condition this should be taken into account when the headlights are designed, in this case there appears to be next to no design features, instead its cheaper to put a comment in the handbook...
but then its not just seat...
however given its a known condition this should be taken into account when the headlights are designed, in this case there appears to be next to no design features, instead its cheaper to put a comment in the handbook...
but then its not just seat...
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