clvincent

a few weeks after i got my GL i noticed looking from the inside the pano roof had small cracks in it everywhere

took it to my detail guy and he washed and waxed it and it looks fine

the truck spends probably 4-5 days full a week under a shade which is certain to make a big difference in arizona
it is my back up car and does not get driven as much

do think this car was probably garage kept its whole life in georgia before i got it, which probably helped too

but so far having it out here 6 months or so no issues

i usually take both cars in for a detail with wax every 3 -4 months , hoping this will prevent any issues with my roof
we will see, i will keep this up to date

N_Jay

I am also conjecturing that atmospheric contamination is part of the problem.
I purposely do not park outdoors at the airport.


Mine was a TX car for the first 5 years, but believe it was mostly garaged.


I looked at (and passed up) a FL car that supposedly spent a lot of time at the airport, and it was very bad.

clvincent

i looked at 3 others before buying this one, all southeastern US cars and the other 3 pano roofs all looked horrible

but i dont know if maybe they had been waxed and cleaned up that it would have made a difference...

Jason B

how about some pics?

johny75

Yes this approach works, I tested it. Start with 600 grit, then 800, 1000, 1200, 1500 wet sanding it and it will look like new. I tested one small spot on the back and it looked smooth and clear. However, it is a lot of work, so I decided not to do the entire roof , so now I have a small polished spot at the back : ) I don't care no one glares through it anyway. Only helicopters can see it .. lol . I have used the same approach on the headlights and I finished them, but they are small surface compared to the entire roof.

N_Jay

Don't forget the UV protectant.

Jason B

So in conclusion, no one has fixed this themselves yet.

angelglo

I looked down at my 2007 GL450 from my bedroom and noticed that my back roof glass was very bad as well. my wife comes over and asks what I was looking at. I tell her that I was thinking about sanding mine down with a polisher and increasingly fine sand paper. She then says, no one can see it. She then ask if it affects the driving and I say no. She then tells me that I have better things to do like clean the house or drive the kids around.

I guess I wont be detailing my roof glass.

N_Jay

Tell her one of the neighbors mentioned it.

Then you get to buy that new dual action orbital polisher!

mrmotoguzzi00

going down to 600 is a little over the top, start at 1500 wet, aka put a hose on soaker and just let it flow over the spot your sanding, use a rubber sanding block that is flexible enough to conform to the curve of the plastic. I'd say for every sq ft or so of surface you may want to change the sand paper... if you don't you just sand longer for the same effect as using new paper Your Choice...

With a little practice you will feel the rough surface coming off aka it gets easier to sand, move to the next spot

At this point you can graduate to increasingly smoother sand paper and go over it again... 2000 then 2500, then 3000 or spend a bit of time with that buffer and cutting compound... go to an autobody paint supply store for the sand paper don't use home depot/lowes

with the 3000 it should look a satin paint job when your done...

time to buff it out...

don't skimp on the compound amount....

then go to polish with the buffer....

then wax....

Should be very shiny at this point


Mike

N_Jay

Are you selling or keeping?

If selling wax is "OK", but if you are keeping you need to have the surface sprayed with a UV protectant clear coat compatible with the acrylic material.

You can go 1/2 way by using a DIY UV protectant spray, but will need to clean, lightly polish and reapply every year or so.