My S4 is doing that a little bit too. Someone told me it was from the harsh detergents used in automatic car washed getting in between the clear coat(or whatever that coating is) and the metal.
I purchased some shadowline black vinyl but the project is kind of on the back burner since the trim goes pretty well with my summer wheels. I’ll have a go one of these weeks though.
i have two solutions that have worked very well for me.
Meguiars M105, microfiber towel, dab some on and rub the fuck out of it until it starts creating heat. M105 does not break down so you can work it longer.
Another good option but not as good on heavily damaged trim is P21s Metal Polish. Dont get it mistaken for the polishing soap which works well too, it is the best metal polish i have ever used to date and i have used a lot.
Best bet though, m105. great to keep around anyway. i polish exhaust tips with it too. its a fantastic do everything tool for the average detailer
According to squiddy, it’s galvanized aluminum.
2nd though for M105. I use it for polishing all sorts of metal but it did nothing to my window trim. It’s oxidized under whatever coating is on there. I might just vinyl it with the stuff that looks like stainless from 3M
I should get you guys some good photos so you can see. It’s weird. It looks like ‘oh I’ll just wipe that off’ but it doesn’t leave.
galvanized or anodized? If its Al it should be anodized, if its ferrous then galvanized. It may be a clear anodized Aluminum; if the clear anodized finish gets worn through the the aluminum could oxidize, Alumina is white and super hard, which would explain the difficulty in removing it.
Whoops meant anodized.
so figuring its Aluminum, the discoloration is Aluminum Oxide (white solid).
Now regarding hardness, natural AL2O3 has a 9.0 Mohs Hardness (talc being 1, diamond being 10), so trying to abrade it off of the aluminum is going to be tough (as D mentioned, you have to build heat up and really work at it).
Problem is the kinetics of the oxide formation strongly favor having the oxide coating… ie if you rub it off its just going to come back unless you seal it. If the clear anodize is damaged (you’ll have to burn through it to get to the spot anyways) then there is no seal and the metal will oxidize soon after anyways. So you’d have to clean it up then paint over it right after.
You need a strong acid to remove it chemically, I think HF works well, but anything strong enough to work well will be strong enough to fuck up other stuff.
Have same issue. I tried hitting a small strip with Meg’s 300 and microfiber pad on a DA. No luck and I didn’t want to apply I mch pressure. The cloudy finish came back
I’ll deal with it. I feel that if I take off the trim to wrap, it will never fit right again.
I think the trim snaps on pretty good. It’s just that you can’t remove it (well not all of it). You have to replace that rear window (the little small triangle one)
^yeah iirc the trim is riveted in and is a bear to remove… you can paint it on the car though, thats what I did
One of the pieces of trim (driver’s side rear door) on my RS4 has the same issue, and it has been this way since I got the car in 2009. The trim on the RS4 is different than the S4. I have tried a few things to remove the “milkiness”, including Mezerna polishes. Nothing has altered their appearance at all.
I think the “corrosion” is under the clear and on the surface material. So, the only way to address is to completely remove the clear and polish the metal. But then you have a piece that doesn’t match at all with the rest. It sucks but I have just accepted it and moved on…
Yeah, it’s not really a big deal. It’s fun to bitch though 
I’ll ask my dealer if there’s anything they can do, or if there’s anything outstanding. The S4 guys with similar (but not the same) problems and pursued it were succesful. I mean if after 3 years your paint was peeling or bubbling or was all cloudy, they would certainly warranty that. Same if your Catalytic Converter failed. No reason they shouldn’t warrant the trim. It’s not like it’s from wear and tear…it’s just a bad design.
I’ll tell them that since this is likely to just re-occur if I get more aluminium trim, I’d rather get the black stuff and be done with it.
Update
I’m asking the dealership about it this week.
Out of interest, I asked a parts counter for pricing on the aluminium trim, and the matte black trim.
Here’s the response…
++++++++++++++++++++++++++++
Aluminium
Roof Trim
Left 8E5-853-703N-1L1 $293.00
Right 8E5-853-704N-1L1 $293.00
Rear window quarter trim
Left 8E5-853-345F $247.00
Right 8E5-853-346F $237.00
Front window
Left 8E0-853-765B $72.00
Right 8E0-853-766B $72.00
Rear window
Left 8E0-853-767B $100.00
Right 8E0-853-768B $100.00
$1414
+++++++++++++++++++++++++++++
Black trim
Roof trim
8E5-853-703M-1P9 $172.00
8E5-853-704M-1P9 $172.00
Rear Window Quarter trim this is calling for a complete window replacement you cannot buy the trim separate on this one
Left 8E5-845-299T-NVB $109.00
Right 8E5-845-300T-NVB $109.00
Front window
Left 8E0-837-477C $102.00
Right 8E0-837-478C $102.00
Rear window
Left 8E0-839-477C $53.00
Right 8E0-839-478C $53.00
Total $872
++++++++++++++++++++++++
Interesting that the titanium package trim is actually cheaper. I am curious if it is possible to actually re-anodize the aluminum trim. It would be well under $100 to have it anodized if it is infact possible.
if it is indeed aluminium…I haven’t really even checked too thoroughly. Is your car ti or non-ti? Any signs of this?
I frankly hope they can’t fix it and just decide to replace it. I’ll make the suggestion to use the black trim to save Audi a few bucks because i would rather have it black anyway since the aluminium will likely go milky again in a couploe of years, right when my warranty expires and i like the black trim.
Mine is titanium package, I believe it is painted finish from the factory.
mine was milky, i dremeled it with a little buffing tool and with rubbing compound and got it almost new… i sealed it, waxed it and glazed it… looks funky fresh now!
You used a dremel? That must’ve taken forever.
I went to the dealer. Service manager needs to look at it. If it’s just trim damage/defect, it will be replaced. He’s going to determine if there was an outside influence (I guess determine if I’m a moron and poured acid on my own car lol)
I will clarify, if they elect to replace it, if I can go with the black stuff instead. Hopefully I can.
Apparently this isn’t common…but also not rare. He said it’s odd to happen on a 2008 RS4 because usually the ones that they’ve seen with this are 2007. Audi apparently changed the process/part at some point.
also this is only covered under your original 80kms/yrs warranty (or 50,000 miles for you yanks). CPO won’t cover this, so good thing I took it in. My original Audi New Car Warranty expires in like 4 weeks.
Here’s the aluminium trim on my Avus RS4 with my Ti package wheels vs. an actual Ti package Avus RS4 (so you can compare black vs. aluminium)
Got a vote?
http://audirevolution.net/addons/albums/images/611266829.jpg
Ti package all the way.