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[Greenbay packer]

Hi All, Just failed the MOT of OS headlamp issues as its 'not giving the right pattern' (NS is also not good).  MOT man used this as an excuse to sell me an expensive Bosch bulb as he said poor bulb quality could be the cause (I only realised when I got home that he'd sold me an H7 bulb when both my dip and mains are H1 halogens so he'll be getting that back), but I suspect it could be more to do with lens being misty.  I did use a headlamp restoration kit on it and improved the lens quite a bit, but perhaps not enough.  My main question is are all the headlamps that take halogen bulbs the same and interchangeable - my one has the GM number 90457764 YX on it, but I can't find this listed anywhere.  I have found headlamps that look identical but have the number 90457572 YX so was wondering if I could use one of those if I need to replace?  A lot of the time the GM numbers seem to be production numbers rather than fixed part numbers but I've not been able to find anywhere that these units are identical.  Any help would be much appreciated! The other MOT failures were a brake imbalance and handbrake problem which I might post separately.

[RobG]

Pre `98?

[RobG]

Pre `98. Replace with projectors 90566798 RH   90566797 LH

90457764 YX is the production number. part number is 90487572   

[Doctor Gollum]

Also, all the headlight units list their required bulbs on a sticker visible with the bonnet open

[Greenbay packer]

Pre `98?

Sorry, forgot to say 1996.

[Greenbay packer]

Pre `98. Replace with projectors 90566798 RH   90566797 LH

90457764 YX is the production number. part number is 90487572

That is confusing - if that is the case my ones just have the number 90457764 YX and no part number, and the ones I've been looking at 2nd hand as possible replacements just have the number 90487572 YX and no production number.  Just realised I made a typo in my previous post and put 90457572 when I should have put 90487572, but from what your saying the latter is the right number for halogens.  Just wanted to be sure there was only one lens pattern for the halogens if I'm just buying one for now. 

[RobG]

Two lens patterns. Yours (full of ribbed lines, old ones, pre `98) plus the projector style (clear lens, very few "lines")

[RobG]

Old style pre `98. Not very good pic quality

[Greenbay packer]

Two lens patterns. Yours (full of ribbed lines, old ones, pre `98) plus the projector style (clear lens, very few "lines")

Brilliant, thanks.  Are the projector type a direct swap as far as the bulbs, wiring etc are concerned?

[RobG]

Direct swap and far superior, especially with Osram Nightbreakers or similar for dipped beam

[Greenbay packer]

Thanks again, that'll give me another option.  With regard to bulbs and my problem with the MOT, do you know if different makes of bulb do have an effect on the pattern produced or is the problem more likely to be caused by the surface misting on the lens plastic which I'm still trying to polish out?  Just wondered if the 55w brighter Xenon filled bulbs (i.e., not Xenon hid) would make any difference?

[cam.in.head]

the bulb itself can cause problems especially cheaper unknown brands. its usually because the filament should be in exactly the same place inside the glass.good makes usually get this absolutely spot on but others can have the filament slightly off centre.same goes for the metal holder around the bulb.this is usually electrically welded on in 3 spots. any misalignment of this or the filament is like having the bulb out of alignment with the reflector.this will interfere with the beam pattern.if the reflector is good and the lense is polished up clear then a good bulb should sort it.

[Greenbay packer]

the bulb itself can cause problems especially cheaper unknown brands. its usually because the filament should be in exactly the same place inside the glass.good makes usually get this absolutely spot on but others can have the filament slightly off centre.same goes for the metal holder around the bulb.this is usually electrically welded on in 3 spots. any misalignment of this or the filament is like having the bulb out of alignment with the reflector.this will interfere with the beam pattern.if the reflector is good and the lense is polished up clear then a good bulb should sort it.

Thanks for that info, very helpful.

[Greenbay packer]

Direct swap and far superior, especially with Osram Nightbreakers or similar for dipped beam

Which dip beam bulbs are recommended for my early style headlights?  Would you still recommend Nightbreakers (Unlimited), or there's the Osram Silverstar, or the Osram standard?  Thanks again.

[Keith ABS]

Nightbreakers

Keith ABS

[Greenbay packer]

Thanks.