E36 Headlight Intake Duct

  Modify a spare headlight to function as an air intake duct.

If you're like most US-model e36 owners, you've probably replaced your poor-quality DOT Plastic lensed headlight assemblies with nice aftermarket glass units. What should you do with the old headlights... Throw them out? NO! Not yet!

Make at least one of them useful and turn the driver side lamp into an air intake duct for track days.


Any information presented or implied is for entertainment purposes only. A car and related parts can be very dangerous to work around. Please exercise extreme caution when performing any kind of repair or modification. Neither I or any affiliated parties can be held responsible for any problems or accidents which may occur.

Here we have a spare left(driver-side) headlight.
The intake filter sits right behind the headlight, and would benefit from a supply of cold air.

To do this, we will cut this spare headlight to function as an air intake duct.
To begin, locate a sheet of aluminum foil large enough to sit under the entire bottom of the headlamp assembly.
Now, set your household oven, and preheat to between 225F (107C) and 250F (121C).
After the oven is hot, place the headlight on top of the aluminum foil and set it on the center-rack of the oven.

After approximately 10 minutes, remove the headlight from the oven, and attempt to pry the rear reflectors from the housing with a flathead screwdriver.
If it does not come off easily, put it back in the oven for a few more minutes and try agian.
Alternatively, if you are impatient, you may choose to break the reflectors by cutting or cracking and breaking them off (this can be messy).
After the reflectors have been removed, this is what you should have.

Now using a rotary cutting tool (or a saw), cut a rectangular opening on the front of the headlight.
Be sure to wear proper eye, ear and respiratory protection equipment, as particles can be dangerous.
Sand down all surfaces on the outisde of the (formerly) plastic lens. This will prepare the surface for painting (if you choose to paint it).

Boil enough water to submerge the headlight in a sink. Place the headlight, pointing downwards (rear faces you) into the hot water, and let it sit for a minute or two.
Once the lamp has warmed up in the water, carefully remove the headlight from the water (be careful, the water will still be very hot).

Using your hands, point the headlight away from yourself, and use both hands to push the glass lenses out of the housing by applying pressure to the glass from the back of the housing.
Dry the hosuing and you're done! At this point, you can paint it or just leave it alone (as we did here)

A helpful note for those participating in SCCA Solo2 Autocross:
Using this intake duct may bump your car up to a higher running class. Ask about the rules before you run with it installed!