sealing Z4 headlights to stop water condensation buildup

[wiseguy]

I thought I'd share my work to stop the ongoing and reoccurring water condensation in my 2007 Z4 xenon headlights. Two mechanic shops refused to attempt this, and BMW wants to sell me a complete headlight assembly for $500.00. The headlight works fine. This is a simple $4.00 rubber gasket fix, but that's the BMW way: don't offer an inexpensive remedy when you can sell a $1,000.00 replacement. I wonder why we have a throw-away consumer culture.

Lacking a lift, a paid the mechanic for 2 hours of labor to remove and reinstall the bumper and both headlights. I was surprised to see a fair amount of dirt particles and small stones inside the headlight assembly. I got some of them out simply by tilting the headlight this way and that. There was also some old gasket making material (either rubber butyl or silicone) on a portion of each headlight seam. I further noticed what appeared to be mineral buildup on one joint of one headlight, the sort that appears around water faucets from the dissolved minerals in the water. No wonder I had condensation.

I will be sealing:

1. The joint around the clear headlight lens,
2. the joint around the rear headlight bulb cover (It can be easily slit and reapplied if a bulb goes out),
3. the three apparent "weep/air/drain holes" around the top of the headlight. I will circle them in red in the photos. BMW put drain holes at the top, when the water pools in the bottom. Typical BMW move. This is why my convertible roof hydraulic motor continually floods with water: poor drain design and placement.

Things I used:

91% isopropyl alcohol to clean up the joints to be sealed.
Q-tips to get in the nooks and crannies to ensure they are clean and the silicone will stick.
a cotton rag to cleanup the areas around the joints suing the alcohol.
Permatex clear adhesive sealant silicone RTV

I used the rag and q-tips, soaked in a little alcohol, to clean the joints from the bottom up. By that, I mean I cleaned the bottom of the headlight so that any liquid alcohol squeezed off of the q-tip or rag would not drip into the gap inside the headlight. Alcohol evaporates quickly, so by the time I flipped the headlight over to clean the other side, the joint I cleaned was dry.

I then allowed both headlights to sit for a few hours in a warm room, to increase the curing of the slilicone when I apply it. The room was heated to 70 degrees F / 21 degrees C.

I will post photos below once I find a photo hosting site.

I welcome all comments, questions and suggestions. I will update this thread periodically to let you know if my fix worked long term.

[wiseguy]

Click on the pic to see a larger version.

The before headlight, removed from the car.




Items you will need:






headlight weep hole/ drain hole 1



headlight weep hole/ drain hole 2



headlight weep hole/ drain hole 3. This one lacks a rubber "elbow pipe" style cover on either headlight.



q-tips after both headlights are clean

[tug]

Quite an extensive job there mate. Hope it solves the problem.

When i had the condensation problem with my lights i just took the back cover off, dried the lights out with a hair dryer, reversed the seal and smeared with vaseline. Some say to use silicone but this was 2 years ago and not had the problem since.

Cheers, tug

[bigwinn]

Quite an extensive job there mate. Hope it solves the problem.

When i had the condensation problem with my lights i just took the back cover off, dried the lights out with a hair dryer, reversed the seal and smeared with vaseline. Some say to use silicone but this was 2 years ago and not had the problem since.

Cheers, tug

Have to say same here- reversing the seals worked a treat for me

But ditto- good write up

[Jamturbo]

Same issue, lots of condensation which was sorted by hairdryer (cool temperature) and new covers. Almost 3 years later still clear. The covers don't cost too much if the seals are knackered. Believe I got the tip off this forum.

[MichaelK]

I've got a weird issue with the passenger side xenon on my z4........inside the lens is alot of fine grit particles, you know the sort that you get all over the arch liner and bodywork when you've been driving in rain.
Ive no idea how I'm going to get rid of it without taking the outer lens off, which I dont want to create possible leaks.

Anybody know of any companies that can do such a task of removing the lens?

[Scooba_Steve]

Anybody know of any companies that can do such a task of removing the lens?

Doubt any will touch that, you have to cut it. Blowing out with shop air might work, also worth cleaning the lenses.

[MichaelK]

I dont understand how so much has got in there to be honest

[wiseguy]

I've got a weird issue with the passenger side xenon on my z4........inside the lens is alot of fine grit particles, you know the sort that you get all over the arch liner and bodywork when you've been driving in rain.
Ive no idea how I'm going to get rid of it without taking the outer lens off, which I dont want to create possible leaks.

Anybody know of any companies that can do such a task of removing the lens?

MichaelK, I can't answer your question, but I found a small amount of pebbles and dirt in my headlight. Clearly if that can get in, water can as well.

You could try using a heat gun around the lens and headlight module joint and pry those apart. I'm guessing they are sealed with butyl tape, which gets more pliable when heated. Just don't get the plastic too hot for obvious reasons. Clean the inner side of the lens and then reattach with butyl tape.

[wiseguy]

These photos show the large gaps in the headlight wherein water and dirt can get through. Click on a pic for a larger version.

Note the large pebble in the gap.







For size reference:

[wiseguy]

So my hours of sealing the entire headlight assembly was a waste of time. Click on the pic. It's a tropical greenhouse in there. I was gutted to see that today.

Either my mechanic damaged the silicone seals during the reinstall or ???

BMW says they do NOT offer a seal I can replace (the seals y'all said you greased, or turned inside out, or replaced). Do y'all have a part number I can reference? They would prefer to sell me complete headlight assemblies for $500 each. That is ridiculous, but that's BMW for you. Make a crappy part, then charge $$$$ for it.

I can't drive my car at night (bulbs are not coming on) or if it might rain. This car is turning into a delicate snowflake.

[Ewazix]

Quite an extensive job there mate. Hope it solves the problem.

When i had the condensation problem with my lights i just took the back cover off, dried the lights out with a hair dryer, reversed the seal and smeared with vaseline. Some say to use silicone but this was 2 years ago and not had the problem since.

Cheers, tug

Have to say same here- reversing the seals worked a treat for me

But ditto- good write up

... and another one cured with hair dryer and some non-setting silicone sealant on the back cover seals. All cars will get a temporary mist of condensation in certain conditions but it should quickly equalise and clear. But I admire your work

My thought is that if you block the micro holes and hermetically seal the unit without removing 100% of moisture you are risking near permanent condensation (It's difficult to remove moisture 100% unless you are in the Atacama Desert or create a vacuum, and I'm guessing Mississippi isn't exactly zero humidity!). Condensation forms when moist air meets a cooler surface, so minimising moisture with reasonable seals but allowing some ventilation/equalisation is necessary, in this case via warm moist air rising out of the micro holes.

[DMike]

BMW says they do NOT offer a seal I can replace (the seals y'all said you greased, or turned inside out, or replaced). Do y'all have a part number I can reference? They would prefer to sell me complete headlight assemblies for $500 each. That is ridiculous, but that's BMW for you. Make a crappy part, then charge $$$$ for it.

Regarding the seals, looking at realoem there seems to be separate part numbers for everything, even the ventilation grommets, but not the seals. The headlight covers (63126928414 and 63126928413, $14.67 each), however, come with the seals (google image search).

[1536Z4]

The headlight covers (63126928414 and 63126928413, $14.67 each),

I bought the new headlight covers as they are cheap enough and as stated I don`t think you can buy just the seals . I also sealed up the gaps on the front of the headlights with clear "exterior" silicone sealant . I got some spare ventilation grommets from another forum member and fitted these to the weep holes that did not have any grommets . I used a thin layer of silicone sealant around the weep hole before fitting to help keep them in place . All good so far

[bigwinn]

The headlight covers (63126928414 and 63126928413, $14.67 each),

I bought the new headlight covers as they are cheap enough and as stated I don`t think you can buy just the seals . I also sealed up the gaps on the front of the headlights with clear "exterior" silicone sealant . I got some spare ventilation grommets from another forum member and fitted these to the weep holes that did not have any grommets . I used a thin layer of silicone sealant around the weep hole before fitting to help keep them in place . All good so far

From experience, once its cracked (no pun) its sorted for the foreseeable

good work!