Alloy gone 'milky'

Bosco · 28 Sep 2014

Having given my car a good clean at the weekend, I was a little taken back to discover one of the rear alloys has started to go a 'milky' colour - see attached photo.

I am a little disappointed this has happened on such a low mileage car ...that is well cared for. I got caught in heavy rain last month, yet only one wheel has gone this colour.

The car is a low mileage 2011 997.2. I keep it garaged and it is under warranty. Is this an item that should be covered by the warranty?

plavix · 29 Sep 2014

I know of alloys being replaced at OPC under warranty, but for a car less than 12 months old.

They won't be covered under the extended Insured Warranty, but there is no harm asking if you are known to your OPC, spend money there and they like you.

Did you purchase from an OPC? If so, I would speak to the supplying OPC.

Chris_in_the_UK · 29 Sep 2014

Had a similar issue with an Audi after using what the dealer described as an 'aggressive wheel cleaning product'. Cannot remember what the offending wheel cleaner spray was......

DRZ911 · 29 Sep 2014

Looks like an undiluted or highly alkaline cleaner may have been used, or maybe the cleaner was left on for too long.

Worth giving your local OPC a punt on a warranty claim.

Bosco · 30 Sep 2014

DRZ911 said:
Looks like an undiluted or highly alkaline cleaner may have been used, or maybe the cleaner was left on for too long.

I haven't used any aggressive products on the alloys and only one alloy has gone 'milky'.

Worth giving your local OPC a punt on a warranty claim.

Just waiting to hear from the OPC where I purchased.

Thanks for the comments, just waiting on a response from the OPC.

From researching this forums and Pistonheads, Exel and Lepsons have been mentioned as possibilities to repair if not covered by the warranty, though I'd prefer an OPC to action, so I get covered re cost and any future hassle.

Frenchmeister · 30 Sep 2014

I am not saying this is the case in this instance but polished alloy covered by clear coat lacquer will go milky if the lacquer is broken by stone chips etc allowing moisture in and reacting with the now exposed alloy.
Mike at the Blast Shop Carlisle who has done tons of wheels for me will not give a warranty on this type of polished wheel after refurb due to this fact.
That said have a go at the supplying dealer for replacement and use some nice PH neutral wheel cleaner when cleaning them.

MJA911 · 30 Sep 2014

Bosco said:
From researching this forums and Pistonheads, Exel and Lepsons have been mentioned as possibilities to repair if not covered by the warranty, though I'd prefer an OPC to action, so I get covered re cost and any future hassle.

Exel (chrisw on this forum) are very well regarded as you will have seen, Chris did a super job on my alloys, although they are regular painted rather than the polished/laquered alloy design like yours (which I really like). I'd be confident he'll know exactly what to do if you need to go in that direction. With the OPC, logic says that if some kind of damage has led to the milky appearance they may not fix under warranty, but if its a defect in the wheel then they would. Best of luck.

MisterCorn · 30 Sep 2014

Classic problem of the clear cote getting damaged and the alloy being damaged by oxidation. The solution is to have the wheels refaced and re-lacquered. This is very common in the world of BMW. Typically the wheels can be done a few times before they are beyond refacing. Talk to Chris at Excel, he knows all about the options and will treat you well.

MC

Frenchmeister · 30 Sep 2014

A lot of new cars Audi, BMW etc are coming with this tyle of wheel now and the wheel restorers are going to be kept busy in the next few years.

Chris W · 30 Sep 2014

looking at the photo the wheel has been refurbished before.

What should be done when they are refurbished is the edges deburred and given a small chamfer which will prevent premature (but never stop 100%) damage to the lacquer on the leading edges. A sharp edge will get damaged more easily. When this lacquer is breached through cleaning, stone chips, abrasion etc it will allow water/cleaner to react withe the alloy leading to the milky appearance.

Diamond polished alloys like these need a really good lacquer and decent thickness, many choose to ignore this and use cheaper lacquers.

Ultimately when these wheels are made, these are forged Turbo II, this hardens the very top surface and builds in a bit of corrosion resistance. When they've been refurbished the very top layer is removed and the alloy is fractionally less hard making it more susceptible to corrosion, much like a non-forged, i.e. cast wheel would be. This is why cheaper aftermarket alloys go like this within a year. Some wheels are also treated to an anti-corrosion treatment which really is only suitable at point of manufacture rather than refurb stage.

You really need to get it sorted soon rather than allow it to deteriorate. What will happen is the corrosion goes deeper into the crystalline structure of the metal as the lacquer prevents it from breathing. It's not going to heal itself unfortunately...the downside to diamond polished wheels.

A bit long winded answer but hope it helps understand.

Bosco · 30 Sep 2014

Thanks to all for responses, much appreciated.

Re Chris's post, the wheels came with the car and are part of the spec. for the model, a 2011 Black Edition, so they are supposed to be original.

The car is under warranty, so hopefully the OPC will resolve, just waiting on a response.

if they refurbished the wheels before I bought, then hopefully they will acknowledge and pick this up.

Ian Donkin · 1 Oct 2014

Lacquer on polished aluminium never lasts, despite what anyone might tell you; it can't as it has nothing to bond to. Either painted wheels or an anodised solution will give you a better outcome; you gets what you pays for....

Chris W · 1 Oct 2014

Bosco said:
Thanks to all for responses, much appreciated.

Re Chris's post, the wheels came with the car and are part of the spec. for the model, a 2011 Black Edition, so they are supposed to be original.

The car is under warranty, so hopefully the OPC will resolve, just waiting on a response.

if they refurbished the wheels before I bought, then hopefully they will acknowledge and pick this up.

They are original spec but that wheel has been refurbished as I can tell from the edge so don't let anyone tell you otherwise.

RJKflyer · 1 Oct 2014

I'd recommend GTechniq nano wheel coat, once you're fixed up.

Since I've used that, it's a wash with sponge and every trace of dust/dirt comes straight off even when absolutely black.

Used it on my previous RS4 alloys and they were as new when I sold it, and the 2 sets of wheels (summer/winter tyres) I've got on my turbo are also like new.

I remember my E46 M3 wheels did what you have, mainly due to the clear coat being breached and I used to use the 'traditional' alloy cleaners which gradually broke it down.

B16YYJ · 7 Oct 2014

My wife's Impreza STi wheels went like that when it was nearly 3 years old, I had it in for a service and they rang and said we are changing the alloys for brand new ones under warranty as they have corroded around the centres, even though she had slightly curbed them. I was gobsmacked TBH. Hope Porsche do the same for you!!

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