Headlamp low beam lights are anemic

[lfyost1]

My low beam lights are not the least bit bright... high beams are fine.
The inboard lens covers are very cloudy whereas the outboard are bright and clear. I'm suspecting the inboard ones should be clear, too.
Are these clean/ polishable. or is this a replacement situation?

 

[mmm-five]

There is no bulb in the inner housing.

The high beam / dipped beam is done from the same bulb via a flap - aka ‘bi-xenon’.

The Z4M xenon s are not the brightest when on dip mainly due to them being set quite low in the first place, so sticking to the allowable angles it doesn’t throw the beam very far.

The best you can do, and what I did, is:

• Adjust them to their uppermost legal limit
• Take off the headlights to remove any dust build up on the projector lens
• Polish the headlight lenses whilst they’re off

 

[lfyost1]

Is the inboard lens supposed to be cloudy?

 

[mmm-five]

Is the inboard lens supposed to be cloudy?

i
It shouldn’t be cloudy…that would indicate either moisture in there or something causing uneven wear on the outside of the lens.

However, you shouldn’t expect to see any light from the inside housing, other than the angle eye ring.

This photo indicates how the external lenses can look cloudy (left side) and what they can look like when original or polished (right side)…

This shows how the inner & outer lenses look…

…and finally what they look like when illuminated (albeit this photo with aftermarket xenon kit)…

 

[lfyost1]

Thank you. How is the polishing accomplished?

 

[mmm-five]

Thank you. How is the polishing accomplished?

There are kits available with varying levels of polishing compound and a DA polisher...but I'd not risk doing it myself unless I was confident in using polishing equipment, as if you damage them you'll be looking at £1000 each to replace.

 

[RedUn]

You can polish them by hand, it'll just take longer, definitely safer though

 

[warmasice]

..not the brightest when on dip mainly due to them being set quite low in the first place, so sticking to the allowable angles it doesn’t throw the beam very far.

The best you can do, and what I did, is:

• Adjust them to their uppermost legal limit

Totally agree with the above. Had the same issue on my E89 (reading around I learnt that others had the same problem).

I couldn't believe how poor the xenon's were. I had them adjusted while in for a service to the highest legal limit and it's like driving a different car and totally transformed night-time driving.

 

[lfyost1]

I don't mind doing it by hand. What compound/ grit is appropriate? Do you polish both sides of the lens?

 

[mmm-five]

I don't mind doing it by hand. What compound/ grit is appropriate? Do you polish both sides of the lens?

I've no idea - and that's why I said I'd leave it to someone who knows what they're doing

There's probably a 'How To' either on here, or on other motoring fora.

 

[RedUn]

I don't mind doing it by hand. What compound/ grit is appropriate? Do you polish both sides of the lens?

Have you got a pic of the lights?

If it's literally the outside, pick up some Meguiars plastx from Halfords or amazon etc and a few decent microfibres, take your time and it'll come up lovely. I've used this for years for various plastics and it's always done me well.

You can use more aggressive compounds but I wouldn't risk it if its your first time

 

[lfyost1]

Is it just the outside of the lens, or the inside as well?

 

[firebobby]

Put on a photo of your lights