Technical Headlight condensation

[Mick F]

Totally clear this morning despite a heavy dew.
I've checked thoroughly, and there isn't a crack, chip, or blemish on the light.
Where the condensation/moisture came from, I ain't got a clue.

Removing the cover has worked. I may never put it back on, and probably remove the other one.

Mick.

 

[DaveMcT]

A cloth bag containing dry rice will absorb moisture.

The headlight body is made from a hard plastic. It can easily be cracked when the glass and the glass seal are good.

 

[koalar]

I try one last time

In side is a halogen bulb give of roughly the same energy as a one foot square of a cast iron radiator

Which is good enough to dry your cloth on

You just need to switch it on while let it vent

The original poster has a damaged seal as per their photograph.

I have dried lights out where they have had a little swimming pool inside

 

[DaveMcT]

The OP said he has checked for damage at the seal and found none. So who knows what's going on. I am simply saying that you can do all you like to dry the interior but if the case is cracked it's all a waste of effort.

 

[koalar]

The OP said he has checked for damage at the seal and found none. So who knows what's going on. I am simply saying that you can do all you like to dry the interior but if the case is cracked it's all a waste of effort.

It's got a damaged seal

It been trapped and pinched

It's at the top worst place

 

[Mick F]

I do NOT have a damaged seal.
What is shown originally is a dirty seal.
I've cleaned it and put it back and coated it with Vaseline.
I dried the lens with a heat gun, and all was fine and dandy for the day, but the next day it was a bit clouded.
Going for a drive with the dipped beam on helped, but it was worse the day after.

The only thing that has worked, was to leave the cover off, and it's still fine now.

Mick.

 

[koalar]

The water originaly entered here when seal got pinched at sometime I the past

Looks good your last photo

 

[DaveMcT]

All because it's too hard to remove the bumper to check the headlight properly.

 

[Mick F]

Good afternoon guys.

We've had sunshine and dry breezes, and with the car pointed south when at home, the lens was continually and utterly clear. Remember, the cover has been left off.

I had planned - note the word HAD - to park up at home and leave full beam on for an hour or two, with the battery charger at the ready.
Trouble is ........ and correct me if I'm wrong and I welcome advice .............. is that with the ignition off, you can't leave the headlights on, full beam or otherwise. Consequently, I gave up with that idea.

Meanwhile, the cover remained off until this afternoon, and the lens was clear and fine as usual recently.

Today, we've had sunshine again and the car is still pointed south. I went out, popped the bonnet, fitted the cover, and closed the bonnet.
Half an hour later, the lens is misting up. No rain, no damp, no nothing. Just been out again and removed the cover.

Car not moved. Dry and clear lens. Pointed south in very dry conditions with some sun. Fitted the cover, and half an hour later it's misting up.

"Mystified" sums it up.

Mick.

 

[jrkitching]

It's a mistery (sic).

 

[Mick F]

Less than two hours later, the lens is clear .......... again.

Cover on = condensation
Cover off = no condensation
Less than two hours between the two statements.

Mick.

 

[DaveMcT]

Cover off - zero condensation because the moist air can escape.
Cover on plus condensation because the moist air cannot escape.

You have moisture inside the case. Its a plastic box with a glass lens glued on the front. Leave the cover off and you'll get dirt inside that damages the reflector. So you have to find where the water is getting in. Cracked black plastic case is the most likely but a bag of desiccant inside the headlight for a few days might be all it needs; especially if the cover has ever been fitted badly and allowed water to get in.

 

[Mick F]

Been giving all this a deal of thought.

Not one single car we have ever owned, has had a "waterproof" cover on the backs of the headlights.
Dunno why Fiat Pandas have them, but none of our others have including the Toyota Yaris we have.
I'm not going to remove the front bumper to remove/dry out/replace the light.
I'm doubtful that the rear plastic of the headlight is cracked, and I'm doubtful that there's damage to it.

Daughter2 bought this Panda brand new, and she and I know the car very well indeed.
The headlight has never misted up before, and none of the bulbs have ever been replaced, so the cover(s) have never been off.
The car has never been in an accident, and never had a bump.
106,000+ miles and nineteen years old.

The light mists up, there is no doubt. Therefore something has changed in the last two months since we bought the car off Daughter2.
It's chucked it down today, and the cover remains off. The lens is completely condensation-free.

 

[Mick F]

The cover went on on Sunday. Today is Tuesday.
The lens is completely clear despite rain and and the car being a washed and with using a pressure washer.

Mick.