Perspex headlight covers - to seal or not to seal?

[PeterAllen]

I appreciate my covers are not quite the same as the Datsun covers but the issue should be the same.

 

I'm ready to mount the perspex headlight covers but it strikes me there could be a problem with condensation and thus transparency during rainy periods. The headlights (Moke) have a rubber seal which should prevent any moisture coming into the enclosed area from splash under the front guard but I wonder should I attempt to seal the perspex covers to the bodywork as well? If moisture does get in it will be a PITA to remove the covers and let it dry out.

 

I wondered if I should drill a drain hole through the fibreglass under the headlight rim and allow small gaps to remain where the perspex cover doesn't fit snugly to the bodywork, creating some kind of airflow/ventilation, or will that just encourage condensation under the covers?

 

Does anyone have experience with these types of covers or any comments? Thanks

 

[PB260Z]

Hi Peter

 

Whilst I have no experience in the exact situation you are looking at, I have had a bit to do with Driving Lights over the years.

You find that most of the better quality driving lights on the market incorporate some sort of breather in the body to combat the condensation issue.

 

Hope this helps

 

Cheers

 

PB

[oldmates260z]

I have covers on mine but as I do not drive it in the rain (not because I do not want to, it just never rains) so I have not had any water ingress issues.

 

I would say (not from experience) that you need only to have drain holes to let the water out, not to let air in. Any opening in the direction of travel will allow water to get in while driving and then with the heat of the head light you may and fogging issues.

[Enzo]

Hi Peter, I have a couple of small drain holes in the bottom of mine. 3 mm. When the Perspex was not sealed to the body, I had trouble with moisture getting behind the lens. Now that they are sealed I don't have problems in the rain. I figured that with everything sealed and the heat from the lights, a breather hole would not hurt.

David

[zedevan]

I believe OEM headlights have small PTFE (gortex) vents - so if you have an old waterproof jacket (or get one from an op-shop) made of the stuff you could cut it up and stick it on. The intention being to let it breathe without letting moisture in or out. It also typically starts to weep if left in contact with water for more than half an hour, so if it was at the lowest point it might slowly let drips come out should they ever get in elsewhere.

[PeterAllen]

I believe OEM headlights have small PTFE (gortex) vents...

 

Positioned where?

[Zedman240®]

When I worked at Hella manufacturing OEM headlights for Ford, Toyota etc, they had vents in the rear housing that looked like small barbed hose fittings with a small U shaped rubber hose pointing down with a small round sponge shoved into the hole to stop debris from entering.

Unless the headlights have a perfect seal against the bodywork, you could seal the lens covers on but I'd have something small like a 1/8" hole or a gap in the rubber seal as low as possible to stop condensation and to let air circulate.

[PB260Z]

When I worked at Hella manufacturing OEM headlights for Ford, Toyota etc, they had vents in the rear housing that looked like small barbed hose fittings with a small U shaped rubber hose pointing down with a small round sponge shoved into the hole to stop debris from entering.

Unless the headlights have a perfect seal against the bodywork, you could seal the lens covers on but I'd have something small like a 1/8" hole or a gap in the rubber seal as low as possible to stop condensation and to let air circulate.

 

Dimitri is spot on (no surprise) to this day there is still a vent tube on the majority of our headlight assemblies.

I will see if I can get a photo of one tomorrow.

[PB260Z]

Hi Peter

 

Here is a photo of  the vent on my wife's Yaris, not a type that would suit you though.

A quick google images search for headlamp vent will show you a few more .

I think the answer for you may be something like this

 

http://www.gore.com/en_xx/products/venting/automotive/lighting/headlamps-products.html?isAjax=true