C5 HEADLAMP

StevieOMG · Unread post by **StevieOMG** » 20 May 2011, 18:19

I have a Mk1 C5 and the passenger headlight has yellowed. I have tried cleanin the outer but it remains cloudy. I am therefore in the middle of purchasing a replacement lamp.

Being non-techy, my question relates to removal and fitting. Is this any easy task? Any advice gratefully received

wheeler · Unread post by **wheeler** » 20 May 2011, 18:42

It's quite an easy job but i don't know what your abilities are, you need to partially remove the front bumper at the side your replacing.

StevieOMG · Unread post by **StevieOMG** » 20 May 2011, 18:56

Wheeler.

Many thanks. I am spanner competent so any hints/tips you can give me would be most welcome

BX · Unread post by BX » 21 May 2011, 14:59

Try cleaning it with rubbing compound ot Tcut. Sometimes it works sometimes it doesn't. You have nothing to loose

StevieOMG · Unread post by **StevieOMG** » 21 May 2011, 17:02

Have tried a number of cutting compounds but to no avail. It is seriously affecting light output now so better off to change. Would still like someone's experience as to difficulty level

john alexander · Unread post by **john alexander** » 21 May 2011, 18:21

I recently replaced the blown sidelight bulbs on my mk 2 c5 , had to take the complete bumper off . The headlights then take about a minute to remove

dnsey · Unread post by **dnsey** » 22 May 2011, 09:00

When you replace the unit, make sure that the bulbs are the UV filtered type, as excessive UV might have been the cause of the yellowing.

Unread post by **myglaren** » 22 May 2011, 18:26

dnsey wrote:When you replace the unit, make sure that the bulbs are the UV filtered type, as excessive UV might have been the cause of the yellowing.

Excellent advice.
Mine are yellowed and pitted, spent ages trying to buff them up but it also appears they have 'something' growing on the inside of the glass

cachaciero · Unread post by **cachaciero** » 22 May 2011, 18:38

Do NOT ever use cutting compound or any abrasive polish on "good glass", (well plastic). My understanding is that the basic plastic moulding is polycarbonate (Lexan) coated with another transparent compound which filters out UV.
Abrasive polishes remove this filter and over time polycarbonate will yellow when exposed to UV.
Off course if you have already got to the yellow state then polish it with that you like but it will make no difference as the yellowing goes right through the thickness of the plastic.

cachaciero

StevieOMG · Unread post by **StevieOMG** » 22 May 2011, 18:53

Fitted a new headlamp unit this morning. Despite reservations, I part removed the bumper (from the nearside where I was replacing the lamp). Bumper removal was easy - not so with the headlamp. The two lower bolts were easy, the top bolt was not and I had to hacksaw it off and replace with a new bolt. Made sure bulbs were functioning before putting it all back together. What a difference. You can now tell when the lights are on. Thanks for all the advice.

Unread post by **myglaren** » 22 May 2011, 19:14

cachaciero wrote:Do NOT ever use cutting compound or any abrasive polish on "good glass", (well plastic). My understanding is that the basic plastic moulding is polycarbonate (Lexan) coated with another transparent compound which filters out UV.
Abrasive polishes remove this filter and over time polycarbonate will yellow when exposed to UV.
Off course if you have already got to the yellow state then polish it with that you like but it will make no difference as the yellowing goes right through the thickness of the plastic.

cachaciero

They were well pitted and looked as though they had been 'oversprayed' on the upper part mainly but on closer examination all over.
Buffing did improve it but not significantly.
I wonder if mine are yellowed due to my habit of always having dipped headlights on?
Only did the buffing recently and they were already significantly degraded.

Bumper came off and lights came out easily when I had to replace a lost bulb clip.

cachaciero · Unread post by **cachaciero** » 22 May 2011, 19:40

myglaren wrote: They were well pitted and looked as though they had been 'oversprayed' on the upper part mainly but on closer examination all over.
Buffing did improve it but not significantly.
I wonder if mine are yellowed due to my habit of always having dipped headlights on?
Only did the buffing recently and they were already significantly degraded.

Bumper came off and lights came out easily when I had to replace a lost bulb clip.

Steve I doubt that normal use would cause the yellowing, bear in mind that the same lense cover is used with HID's that's an assumption on my part but they look to be identical. Normal filament lamps don't have any significant UV in their spectrum, lots of Infra Red though.
I would put it down to the coating having been polished away before you got the car (dealers are good at extreme polishing of cars !) and normal daylight UV of which there is a lot these days doing the rest

Some chemicals probably don't help either I know that normal thinners used as a cleaner will accelerate yellowing and crazing of acrylic / perspex, don't know about Lexan though.

cachaciero