Halogen headlights filling up with condensation

Post by **alex_holden** » Sun Oct 05, 2008 9:04 pm

Is anyone else having trouble with halogen headlights and condensation on the inside of the glass? It seems to start within a couple of weeks of them being fitted or taken off and dried out (this is on my daily driver which gets used in all weathers). After a few months the constant dampness inside causes the mirrored back to corrode.

I changed the ones on Fenchurch for the MOT a few weeks ago (they were in a poor state after less than 18 months on the road) and the new ones have already got condensation on the inside of the glass again.

I'm not sure how it's getting in there. The rubber doughnut thing on the back is in good condition, I've used a smear of silicone grease to seal it better, and the headlight bowls are the plastic type so they aren't getting splashed from behind. For some reason the right-hand one seems to suffer slightly worse than the left-hand one.

I have considered putting a packet of silica gel in each one, but I suspect that would only increase the time before I need to take them off and dry them out again. I'd much rather prevent the water getting in in the first place.

Post by **Leo** » Sun Oct 05, 2008 9:56 pm

For what it is worth, I had the same problem with the tripod lights on my 1954 Rover P4, and Silica Gel Sachets (the ones that you find in electrical products) did provide a short term cure.

I have since sealed the lamps where the glass is bonded on to the reflector,using Araldite and have had no further problems

Leo

Post by **Sidney'61** » Sun Oct 05, 2008 10:17 pm

Yes I just noticed a couple o days ago that one of the headlights has condensation on my car that doesnt fit in the garage, I'll have to sort it out soon, thanks for reminding me.

Post by **bmcecosse** » Mon Oct 06, 2008 2:51 pm

I had halogens on my Mini that did this Alex - next set I bought I sealed around the glass with clear silicone sealer and they were still fine 6 months later when I sold the car.

Post by **alex_holden** » Mon Oct 06, 2008 3:05 pm

bmcecosse wrote:I had halogens on my Mini that did this Alex - next set I bought I sealed around the glass with clear silicone sealer and they were still fine 6 months later when I sold the car.

Sealed where exactly? I don't want to put sealant where it would stop me changing the bulb or adjusting the aim.

Post by **bmcecosse** » Mon Oct 06, 2008 3:09 pm

Just around the join of glass to backplate - all around the edge. Not anywhere near the bulb entry.

Post by **alex_holden** » Mon Oct 06, 2008 3:12 pm

That joint looked like it was well sealed already but maybe not - I'll give it a try.

Post by **bmcecosse** » Mon Oct 06, 2008 4:27 pm

Mine looked ok too - but I thought it would help - and the new set lasted fine - in fact I now remember I fitted the old ones back on the Mini - and the sealed ones are now on my TR7 - and they are still fine. I just assumed that must be where moisture could enter - the 'boot' at the bulb is not water tight - but it's not bad, and in quite a well protected area, so I don't see an obvious way in there.