Rear light misting

[john c]

The nearside rear light cover on my Chimaera has misted up on the inside of the perspex cover. Can anybody advise an easy way to remove the condensation/mist? The only advise so far is drilling small holes in cover! I am not very happy with this.

[jason1788]

Drilling holes is NOT the answer! You could take the bulb carrier off to let it dry out if it's just accumulated condensation. More likely the sealant has come away partially where the perspex is fitted to the body. Both mine were like it so I pulled them off and re-adhered with black silicon. No problems now.

[Cerby4.5]

I had this problem on my old Chim, I got Tower View to replace it with a new cover and re-fit/seal it. Not an expensive job, but I gather the difficulty is actually getting hold of the covers, making them fit properly (they don't fit straight away) and then having to paint the black outline on the inside of the cover before fixing them! Hence why I asked them to do it.
There is a chap selling a pair in the classifieds at the moment! May be worth a look!
Cerby4.5

[Red V8]

Drill the hole...... doesn't have to be big 2mm is enough... had mine done for ages, took 2 minutes, cost nothing, can hardly be seen with the naked eye, and never had any problems with misting since

[Tyre Smoke]

Alternately remove the light unit inside and wipe a film of washing up liquid inside the perspex - old bikers visor trick.

It works but does need doing ever so often. Better than a hole imho.

[john c]

Red V8 said:

Drill the hole...... doesn't have to be big 2mm is enough... had mine done for ages, took 2 minutes, cost nothing, can hardly be seen with the naked eye, and never had any problems with misting since

[john c]

Thanks to all replies re. rear light misting. Took Red V8's advice & drilled a 2mm hole at base of lense. A slight improvement but very slow.

[tvrbob]

Red V8 said:

Drill the hole...... doesn't have to be big 2mm is enough... had mine done for ages, took 2 minutes, cost nothing, can hardly be seen with the naked eye, and never had any problems with misting since

john c said:

Thanks to all replies re. rear light misting. Took Red V8's advice & drilled a 2mm hole at base of lense. A slight improvement but very slow.

Drilled mine three years ago, no problem. Cars normally have breather holes like this.

[roy the boy]

Just 2 thoughts -

1 - Isn't it because there is a 'hole' somewhere that the lights actually do mist up?

2 - If you do drill a 'hole', do you have to drill it sloping upwards to prevent water running in during rain or washing?

[tvrbob]

roy the boy said:

Just 2 thoughts - 1 - Isn't it because there is a 'hole' somewhere that the lights actually do mist up? 2 - If you do drill a 'hole', do you have to drill it sloping upwards to prevent water running in during rain or washing?

The hole isn't there to let water run out. If you have that much water then more serious work will be needed. The purpose of the hole is to allow the moisture content and temperature of the air inside to equilibrate with the moisture content and temperature of the air outside. When there are significant differences in air temperature the moisture in the air becomes saturated and therefore comes out in the form of dew. Outside this water deposits itself on cold surfaces. That is what is happening inside the rear lights. The polycarbonate surface is colder than other inside surfaces so the dew forms there. Dew won't form if the temperature difference is minimised and the air inside is prevented from becoming saturated by being able to equilibrate over time.

The hole should be no bigger than 2mm and at the lowest point on the cover. A hole this size will not let liquid water through in either direction without significant effort, i.e. jet wash or similar so I wouldn't worry about the angle. Mine were drilled horizontal and as said earlier they were drilled three years ago. I drive this all year round and in all weathers without any water getting in. If you are worried then drill a smaller hole.

[Red V8]

Johnc... give it a little time... one good sunny day and the job's a good un

Also, I'm an addictive car washer and I've never had any water go in..

[bigdods]

Well just to give the other side... my P&J came with the optional holes predrilled by the previous owner on the drivers side. Clearly he only had a 5mm drill to hand and whacked a big hole at the top and bottom. its ok in summer but in winter its pretty much permanently misted top to bottom. Tried to buy a new pair a while back (the other undrilled one also mists but not as badly) but they werent available. Decided to wait until summer and replace the lamps with something abit nicer and do the covers at the same time.

[Cider Andy]

jason1788 said:

Drilling holes is NOT the answer! You could take the bulb carrier off to let it dry out if it's just accumulated condensation. More likely the sealant has come away partially where the perspex is fitted to the body. Both mine were like it so I pulled them off and re-adhered with black silicon. No problems now.

I'd agree. If they came out of the factory with no holes in and there are still lots of them around without a problem that have no holes drilled in, then drilling holes isn't addressing the real problem. I'd want to take the resealing approach, perhaps leaving a bag of silica gel dessicant in the void for a couple of days.

[tvrbob]

Cider Andy said:

jason1788 said: Drilling holes is NOT the answer! I'd agree. If they came out of the factory with no holes in and there are still lots of them around without a problem that have no holes drilled in, then drilling holes isn't addressing the real problem. I'd want to take the resealing approach, perhaps leaving a bag of silica gel dessicant in the void for a couple of days.

I agree with the principle. I drilled holes because it was the simple thing to do and avoided the problem of removing, cleaning, resealing and hoping that the job looked good when finished. I'm sure like me you've seen some awful botch jobs; I just wasn't prepared to take the risk.

[Cider Andy]

It's a fair point that, Bob. What are they like for tackling from the inside, leaving the outside cover in place? I haven't had to do mine, but I bet there's a reason for quite a few getting the drill out!

[tvrbob]

I had not considered creating a vent to the inside. Of course if the air in the boot were hot then it wouldn't solve the problem. I didn't drill mine because I read about it here; it just seemed the right thing to do, I later found others were coming to the same conclusion. If the drill is new and sharp the end result is completely invisible. I was asked last year to photograph the hole so that a fellow PHer could copy it. No matter what angle I chose or how close I got I just couldn't get an image that made the hole visible to the camera. I guess that demonstrates how invisible this can be.

[paulathome]

Why drill a hole at all?
The outer perspex lens is sealed to the body of the car with black sikaflex.
So instead of drilling a hole just leave a little gap in the sealant at the bottom of the lens. That way any moisture inside the lens can drain away at the lowest point.
I have done this and never had any problems with misting.
Just my ten pence worth.
Cheers
Paul.