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  #1  
Old 12-30-2019, 11:49 AM
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Euro headlamp water intrusion issue

Water is intruding into the European headlights on my '88 190E 2.6. The glass lens appears to be bonded to a plastic frame that clips to the main housing (with a gasket I assume) and I suspect it is one or both of these joints. The driver's side is worst, and there is also some intrusion on the passenger side housing.

Water droplets appear on the inside of the lens, and when I removed the back access panel to check out the interior (no apparent leak at this junction), I found maybe 1/32" of water at the bottom on the driver's side housing that I sponged out, then set up a hair drier to blow hot air into the housings for about 5 minutes until they were thoroughly dry. The passenger side had no water at the bottom, but I used the hair drier on it, too, because there was some water on the inside of the lens.

These Euro headlights actually date to 1984 as I originally installed them on my '84 190E 2.3 and subsequently transferred them to the '88 2.6.

Any experience/advice with this issue will be appreciated. I'm hoping I can repair the leak without removing the housings from the car.

Duke

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  #2  
Old 01-01-2020, 12:15 AM
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SOP for headlight retrofitters is butyl silicone. If the perimeter seam is hidden under a
valance or out of normal view, you may be able to apply a bead on the seam. There are
other more labor intensive options but you did say "without removing the housings..."
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  #3  
Old 01-01-2020, 06:30 AM
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I'm "hoping" to solve the problem without removing the housings from the car, but will remove them if necessary. Even covering the housings with plastic, moisture intruded and condensed on the inside of the lens when the car was exposed to condensing humidity overnight.

...anybody have an exploded parts diagram for the Euro headlight housings for a W201? It appears in addition to the glass lens bond to the plastic frame, there is a gasket between it and the main housing and the gasket for the rear access panel.

Do you have a brand name/part number for a "butyl silicone" sealer.

Duke
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  #4  
Old 01-01-2020, 02:55 PM
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it is not easy to troubleshoot headlight leak without photos and clearer
understanding of the point of entry for the water. solving condensation
entry requires different tact vs rain or car wash droplets. how the water pooled
makes a difference as well.

if the lens bonding is confirmed using cement, that is different vs gray butyl
rubber (thermal compliant) sealant which is usually heated to soften, then the
lens pried out. the butyl sealant can be reused ... and even replenished with
more to create a better seal. it can be molded using heat from your fingers
to a rope-like shape and stuffed into the channel between lens and headlight IF
this is what your headlight uses already. if so, i can send you some once you
verify it matches what is in your headlight now

for the outside seam (presuming that is the weakness which can be patched
without removing headlight), basic bathtub sealant can be used (photo)
Attached Thumbnails
Euro headlamp water intrusion issue-silicone.jpg  
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  #5  
Old 01-01-2020, 08:24 PM
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https://nemigaparts.com/cat_spares/epc/mercedes/1/fg/201024/15c/82/180/

NLA
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  #6  
Old 01-01-2020, 09:21 PM
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As I recall, assuming that based on the dates the lights are BOSCH or Hella OE there is a foam gasket the the lens lays against and there are about six or eight galvanized steel clips the secure the lens in place while exerting compression on the glass lens's foam gasket.


Probably best to get them off the car in order to get things done right without breaking anything in the process.



Especially with the OE Euro lights, moisture in the housing is a real problem, the mirrored working surface of the actual reflectors are a vapor deposited aluminum, highly susceptible to degradation when high temps and moisture combine.


Good luck with it
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  #7  
Old 01-02-2020, 03:13 PM
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Thanks very much for the IPB. That will be very helpful.

I'm getting both condensation inside the lens overnight when the temperature drops below the dew point, and a greater amount of water intrusion when it rains.

The car is under two covers, and I even cut some plastic sheet to size to fit over the entire assembly from inside the engine compartment to the bottom of the lens outside, but water is still getting in.

It looks like the lens is an assembly with the glass bonded to the plastic frame that snaps to the main housing, which is what I figured, and my hunch is that this is the source of the leak, so I'll carefully inspect it for a leak and should be able to seal it up without removing the entire assembly, at least along the top.

I'll keep working on finding the leak source and keep you all informed. Since I need to drive it a few times per month, and it's the only car I have in service right now, if I decide I have to remove the housings for resealing I'll have to wait until I get another car in service so I'm not without transportation.

Duke
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  #8  
Old 01-23-2020, 11:31 AM
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UPDATE: We've had very little rain in SoCal since the Christmas night downpour although the overnight low temp usually drops below the dew point, and since I sponged out the water at the bottom of the housing and used a hair dryer to thoroughly dry them out via the rear access panel, there has been no more water intrusion.

I even used a spray bottle and thoroughly doused them around the periphery of the lens, but the interiors stayed dry.

So the point of water intrusion remains a mystery, but I will continue to monitor.

In the process one of the H4 bulb low beam filaments broke. I bought two Hella H4 bulbs on Amazon, $3.25 each and replaced both keeping the serviceable one as a spare. These Euro headlights are actually over 35 years old since I first installed them on my '84 190E 2.3, and then transferred them to the '88 2.6, so the bulbs had good longevity. I don't do much night driving nowadays.

Duke
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  #9  
Old 01-23-2020, 09:39 PM
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At this point if you feel you've confirmed that water entering from the front
and perimeter of the headlight is out of the question, then perhaps consider
moisture entry via condensation, i.e. warm/hot, moist vapor (even smaller
than rain droplets) entering via small openings at the rear of the headlight
and condensing onto cold surfaces. This is not uncommon (almost unheard
of with old, legacy, seal beam headlights)

After a car wash, during rain, etc, your engine produces a sauna like
environment in which the vapor seeps into the headlight and condenses
on the colder surfaces of the front lens.

Some headlights now even incorporate vents with Goretex type fabric over
purposely designed vents.
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  #10  
Old 01-28-2020, 08:05 AM
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I haven't confirmed anything, but so far testing has not revealed the source of the water intrusion and I continue to monitor.

The rear access panel has a built-in vent - a square vertical passage about a half inch on a side, open at the top and bottom with a horizontal passage into the housing.

In addition to the actual housing seals, there is a seal at the front of the hood that rests against the top of the lens and also a bottom seal, both of which protect the assemblies from direct splash.

The next thing I need to do is inspect the wheel wells to determine if there are any seals that might be deteriorated and for any direct route for splash to the bottom of the housings.

Duke


Last edited by Duke2.6; 01-30-2020 at 11:21 AM.
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