2 questions: halogen -> HID and shuddering problem
 

Hey there, first time in this forum and I did a search but couldn't find much so starting a thread. For info I have a 2007 4.4 XC90.
1st question: Headlight covers have gone yellow etc and don't tidy up with sanding etc. Plan is to replace them. I can get some from an 03 model at a steal EXCEPT I believe they are HID or bi- xenon. I know the assembly itself should fit fine but I'm unsure if I can just plug and go. Anyone know?

The other issue I have is I get severe shuddering through the vehicle at certain RPM (generally but not always) or speeds. Generally happens once vehicle has warmed up and under light acceleration on the flat or hills. Accelerating or decelerating remove the problem. Occurs mostly at/around 1500RPM. Tends to be around the 40 and 80km/h marks too. Any ideas? Torque converter has been suggested...
When I get time I'll be checking the spark plugs. I'll likely get the garage to look at replacing the trans fluid when they open as well.

I had the shuddering and there was a problem with the lockup on the torque convertor I recall.

With regard to the headlights - usually they come clean okay with a machine polisher and a semi coarse compound like Farecla G7. I've just done mine for the first time in 5 years and they're like new. Make sure you remove the headlamps and secure them in a workmate or similar to avoid burning through the paint on the panel edges.

With regard to swapping them - whilst the HID (they won't be Bi-Xenon) from a 03 model will physically fit and connect - you are likely to have problems at best with a error message on the dash at worst they just wont work or will flicker.

The headlamp type is programmed into the CEM at manufacture (cannot be changed) and controls how the lights are switched - it's not a simple relay for the dipped beam.

Hi, with regards the 'shudder', do you have significant Coolant loss?

If not, just ignore this post.

Cheers john.l

That’s not true. They wont be active bendy ones but they will be Bi-Xenons as they lifted when you select main beam. I have them on my 54 and they are so much better then the halogen ones.

They would be a straight swap in terms of plug and physical housing but they do draw less current and are likely to give you error messages. By law to have xenon lights you need headlight washers and either auto levelling of the light or the car.

Got my terminology wrong - I meant ABL projectors.

But you do not need washers and levellers on pre-2009 cars with HID and the PWM control on Halogen systems does not switch HID lamps well.

Na, coolant levels are fine.

Had a look at the 03s light fitting and while the housing seems like it should fit no dramas the plugs are completely different. Which I guess means I'd have to have the whole thing rewired etc? If anyone does have reliable info on plugs being the same I'm all ears (and eyes).

Thanks for the info so far!

Whilst on the subject of headlights, mine are misty, tried polishing up one side not fantastic, thought about buying aftermarket and splitting the unit to cannibalise the lens part mine are Bi xenons and even aftermarket ones are £££

Anyone know if this would work and attempted this?

Hi, you can buy a kit which makes the headlight lenses like new. It's a spray and is easy to apply. Probably available in most outlets such as Halfords.

I struggled to make a difference with the generic lens restoration kit I bought as the yellowing was very thick.
I also tried a DA polisher with some rubbing compound which would have worked if I had had the patience.
Instead I got a brilliant result using very fine wet & dry (1500 git & 3000 git) it cuts right through the factory applied coating easily but use plenty of soapy water. You do need a fair bit of elbow grease, but it's worth it.
I then did a DA polish with some glass cleaner and final bodywork polish and they came up like new.
Taking the light units out of the car and done on a bench is better too (especially for you back!)
I recommend that before you drive around/use your nice shiny lights that you protect the lens surface with a hard compound chemical (nano) paintwork sealer (9H nano sealer - small bottle cheap on eBay) otherwise the sun and salt and general road dust will soon have the lenses deteriorating again.

Andy