HID bulb effectiveness - does it decrease with time?

[GoCougs]

So there are many people on both sides - some say it does, some say it does not. Amazingly, the dealership was on the "does not" side. They said they only replace 'em if they're burned out. Thing is bulbs are $100/piece so a bit pricey to experiment with. Either way, it's been ~5 years and ~91,000 miles and the headlights do not seem to be as effective as they once were.

[MX793]

Have the lenses clouded?  I'm not aware of HIDs fading, but lenses definitely haze and that will reduce light output.

[GoCougs]

Not that I can tell - probably best I compare to a new G37/Q40 though. Aftermarket headlight assemblies are $600+/ea (which means factory assemblies are probably $1000+/ea), and I'm not too convinced that the "restoration" kits are worth much, particularly as it comes to not mucking with light transmission.

[MexicoCityM3]

I do think the HIDs on my E46 have gotten weaker over time but not 100% sure.

[Gotta-Qik-C7]

I've had After market HIDs in the G8 from day one and they don't seemed to have dimmed! And the bulbs are MUCH cheaper if you go after market!!

[giant_mtb]

Lenses, even if they appear clear, still benefit from a good cleaning or buffing. Headlights (well, the whole front of the car) take all the road spray all the time, so a strong cleaning or polishing once a year or so is a good idea.  Gotta get rid of the very fine film/gunk buildup that may not be horribly noticeable until you get rid of it.  Easy thing to work into any wash/wax routine. 

As for actual HID bulbs, I've no idear.  Surely there's test data out there, but a lot is probably owned by the manufacturers.

[Rupert]

Are there isocandela diagrams? That would be the way to tell.

[12,000 RPM]

OEM/name brand ones should not. I've bought used bulbs and have done side to side comparisons with new ones and the difference was marginal.

What can happen is the reflector the bulb is in gets burnt..... ze Germans used plastic reflectors for a while ( ) and this was a common occurrence. Older bulbs like the 2nd gen Acura TL ones used to definitely get weaker over time. I wouldn't worry about it.

[GoCougs]

Well, the local O'Reilly's also said HID bulbs don't lose effectiveness with time so that pretty much solves it IMO.

Upon closer inspection, when one got close, pitting on the headlight covers was evident. I got one of those headlight restoration kits and went to town. Turns out the pitting was the problem. What I had lost was peripheral lighting, and that has now been restored. Big difference.

[giant_mtb]

Yeeeee.

What was included in the kit? Was it one of those 3Ms with the mini drill attachment buffer pads?

[GoCougs]

Yes, attachment, pads, compound, wax. Really takes a lot off the headlight covers - I was surprised.

[giant_mtb]

Yes, attachment, pads, compound, wax. Really takes a lot off the headlight covers - I was surprised.

Good!  Like I said, work that into your deep clean or waxing routine and they'll stay fre$h all the time.  Especially important/effective in wetter and snowier places where salt and corrosive road spray are more prevalent.

Also, give your tail lights a wheeling...might be surprised how nicely it'll clean up the overall look of the rear.

[CJ]

You can purchase bulbs from Sylvania directly for half the cost of the dealer cost. My cost at Lexus was $32/ea for the D2R bulbs my car has. The D2S your car has are a little more expensive.

http://www.amazon.com/SYLVANIA-High-Intensity-Discharge-Bulb/dp/B00265FXFY


But I'm glad you just restored them.

[VTEC_Inside]

I believe that most HID bulbs color shift with age.

I'd even heard of BMW selling higher K bulbs as replacements to match the color of the older bulb when one failed.

[Klackamas]

You need to change your blinker fluid.

https://www.youtube.com/watch?v=E6GsXhBb10k

[GoCougs]

Actually, turned out I needed glasses. I have a fairly rare condition (amblyopia, plus near sighted in one eye, far sighted in the other). I've known I had it my whole life but by and large it wasn't treatable. The eye doc said I've probably always had night vision problem but now with the proliferation of smart devices and LED light sources straining eyes throughout the day, and with maybe a wee bit of age-related vision loss, it started to get to me. I also note that the last few years terrible headlights (HIDs, jacked up trucks) and the fact my state/county mostly stopped painting lines on the roads, were factors as well.