Why have headlight diffusers?

joonspoon

175hp. 275lbs/ft.
Nov 18, 2006
361
1
Oxfordshire
Hi folks.
Can someone please explain why my car has diffusers fitted over the headlight bulbs and what they do?
I was looking at an Astra today which appeared to have H7 bulbs (like mine) but no diffuser.
Thanks.
Guy.
 

Fl@pper

Back older greyer and less oilier but always hope
Jun 19, 2001
12,368
25
Gloucester
possibly from the reflector design to eliminate a flare spot as it were

apart from that god knows - think the mk3 didnt have one either

as another wild guess - to stop melting a warm spot on the lense as the bulb is so close ?
 
Last edited:

joonspoon

175hp. 275lbs/ft.
Nov 18, 2006
361
1
Oxfordshire
as another wild guess - to stop melting a warm spot on the lense as the bulb is so close ?

That's a nice thought. Head light on, buy new lens! :cry:

possibly from the reflector design to eliminate a flare spot as it were

I'm thinking light distribution/reflector as well.
The bulbs have a grey/silver cap on the tip of the glass which I guess is there to protect the lens.

Perhaps the diffuser is actually a protection device to save the bulb if something breaks the lens? :shrug:

Guy.
 

Fl@pper

Back older greyer and less oilier but always hope
Jun 19, 2001
12,368
25
Gloucester
all i know in this regard is the latest lexus has them so flimsy they are a common fault to break and its a new lamp if it does

on lexus with it broken its like having a torch as a headlamp - just a round beam and seen one come in with a yellow spot on the lens

so i guess they probably do a combination of both ?
 
Lecatona HPFP (High-pressure Fuel Pump Upgrades)