V70 Diesel Dipped H7 Headlamp bulb failure

[pollitt]

I am currently going through headlamp bulbs like they are going out of fashion, well not quite but about 1 every 3 thousand miles.
Volvo sell a different bulb for the diesel, costing about £12 as opposed to £7 for the petrol, my local dealer knows not why. Excessive vibration from the diesel (as opposed to the petrol) may contribute to the diesel bulb being different.
It is always the dipped bulb (I have not yet changed the main beam in 106K miles) and the offside goes twice as often as the nearside.
The S40/V40 Mkii has had a mod to include a resistance, probably to protect from voltage surges.
I have changed the switch so that I do not start the car with the lights in the on position, believing that there may be a surge at startup, but this is does not affect it.

Q. Has anyone else come across this problem?

Q. Will using a more expensive bulb (re gas Zenons etc) get over this problem as their potential quality may withstand whatever the problem is?

Q. What is the difference between the Petrol & Diesel bulbs?

Not a serious problem but hopefully someone out there can shed some light on this annoyance, knowledge is power :-)
Thanks
Al

1999 V70 Diesel
Previous
1999 V40 1.8
1984 240 2.3 Estate

[liuleichan]

>Q. Will using a more expensive bulb (re gas Zenons etc) get
>over this problem as their potential quality may withstand
>whatever the problem is?

More expensive bulbs (higher gas pressure, plus more xenon in the mix (H7s started their life with xenon in the gas mix)) aren't likely to help you - sure they may _possibly_ be constructed better, but the "improvements" don't lengthen the service life, they shorten it.