Perpetual moisture



This topic has been hashed over I don’t know how many times, BUT still there is no concrete solution as to how to keep the moisture OUT.

Sealing the original seal again doesn’t work with these lenses.

I took the headlamp off the van (2000 Olds Silhouette) and dried it out with a hair dryer (you can’t get any rag or paper towel in there).

There had been quite a bit of moisture in it when I twisted and turned the light while dumping the water out trying to find where this moisture got in.

No such luck. No opening anywhere around the lens.

How is the moisture building back up again and again?

Today the lens (inside) is covered in moisture.

The headlight bulb isn’t lit during the day in good weather.

DRLs are law here in Ontario and these are part of the front turn signal system on these vans.

I even tried to dry the lens off by leaving the headlights on one day while on a long drive but that didn’t work either.

I don’t want to fork out the big bucks to replace these ones.

Anyone care to venture a solution?


I should have added: This moisture build up has been occurring BETWEEN washes and rain storms. The temp has been in the 90s for a while now.


I don’t think you will ever find out how the water got in or be able to seal the leak. I am afraid you are going to have to bite the bullet and spend $200 to replace your headlights.



I was afraid that’s the answer I was going to get.

I doubt finding a used headlamp or two will be a problem as this van has two identical sisters to choose from.

I’m only wondering if the fault will be repeated.

Think for a sec on this: would headlight assemblies on damaged vans in a scrapyard which have been facing the sun be subject to the same problem mine are having?

I’m not too concerned about the plastic lens ‘cloudy look’ as that can be fixed.

Here’s another question: would it be possible for moisture to seep through ‘sandblasted’ plastic lenses?

The van has 135k kms (84,375 miles) put on over a variety of road surfaces.


The problem with headlights out of a used van is that they are unpredictable. If there is water present in the lens then obviously you would pass but just because it is dry does not mean it is not cracked. If you could get the salvage yard to give you a decent guarantee then I would say go for it if they are cheap enough.
I do not see water seeping through sandblasted plastic. I would be concerned with the area where the lens attaches to the housing, the lens, and the seal on the bulb itself. If you decide on wrecking yard lights try to find some that still have bulbs in them.
Look them over very carefully as it only takes a hairline crack to allow moisture in and remember a new aftermarket set costs less then $200.00.


Try an outfit called Certifit. I bought a couple of turn signal/brake/marker units from them that were OK


These lenses you have may be salvageable. These lenses should have a weep hole on the underside of them. After a bit of time, these can get plugged up, and retain moisture inside the lens. I’ve had to use tooth-picks and bent paper clips to clean these out. I purchased some after-market tail lights once, and they started to fog up on the inside. I drilled a small 1/8" hole in the bottom where it wasn’t noticable, and haven’t had a problem since.


Thanks guys, I think I’ll try the drilled hole method.


Contrary to what bustedknuckles said headlights do not have weep holes in them. They are to be completely sealed that is why even the headlight bulbs have o-rings. A crack in the seal, o-ring, or housing will allow moisture to enter the headlight. Drilling a hole in the bottom will allow accumulated water out but the moist air will remain. That moist air will continue to condense on the inside of the lens. Drilling the holes will have no adverse effect but I don’t think it will help either.


If you want to get vapor out you will have to drill a hole close to the top. Either way, you have little to lose by trying since nothing else works.


Points taken.

These condensated lights are what is called progress?

If it is, I’ll go back to the 50s,60,and 70s thank you.

Geez, I had an '88 Chev Corsica for 11 years and never once had this problem.

I ain’t shelling out no $200 for new ones either.
I guess I’ll just have to put up with it. I don’t want to spend any money aside from normal maintenance now.


I understand your view point on this issue. That is why I still choose to drive my 69 Dart. I talked to a bodyshop friend who had a recommendation for your problem. Get yourself some cotton rope. Feed as much rope as possible into the headlight through the bulb opening. The cotton rope should soak up the moisture, then just pull it back out. Then drill two or three small holes across the very bottom of the headlight. He also suggested driving with the high beams on during dailight hours. Hope it helps.


The moisture is coming from the humidity in the air. If the lamp housing is not perfectly sealed, then the atmospheric air can and will enter the housing along with the water vapor. It will condense when the temperature falls below the dew point for the amount of humidity in the housing. Humid air can enter very small holes, condensed water needs a much larger hole to exit. Drilling holes may make the problem worse if you do not have a way for the air to exchange readily.

If you want to fix it on the cheap, one way might be to remove the housing, install a dummy lamp and submerge it in water to look for bubbles escaping. Lightly pressurizing the housing would help to identify leaks. Freeze the assembly with the lamp out, then install the lamp and put it in the sun while submerged to increase the internal pressure. Or perhaps use a compressor with a needle valve to increase the pressure through the lamp oring. Some thoughts anyway.