Hi everyone,

 

I have a set of 20" rotator's on my a6, i've noticed a whiteish layer on the grey area of all four alloys, just very lightly - when I wipe with a damp cloth it goes away but whenever it dries the white scum is back again, any ideas what this could be?

I cant seem to get rid of it

How is the car generally washed ‘b’? 

Kind regards,

Gareth. 

Hi Gareth,

 

Generally washed with foam spray that doesn't contain any thinners or costic, occassionally alloy acid is put over the rims to clean them

Hello ‘b’,

Foam spray not containing any caustic? or acid? Not sure, but be surprised if it isn’t. 

Alloy wheel cleaner? Certainly acidic. 

Can I ask if you are using a pressure washer as part of the foam cleaning process? 

If so, you are aiming (harmful) chemicals at the car at a fair old pressure/speed and they will inevitably attack the lacquer finish on the car and it’s wheels. I’d be very surprised if your current problem is not cleaner chemical/cleaning process associated. 

Appreciating it’s ‘not so much fun’, but I would be sticking to a washing regime of hose, bucket and sponge - and car wax shampoo, which is far less aggressive. 

Kind regards,

Gareth. 

@bf22 hi there, unfortunately this is something strangely known as 'white worm' - which is just the lacquer lifting off the diamond cut edges/face of the alloys. It is an inherent issue with diamond cut wheels and there is nothing you can do to 'undo' it unfortunately. 

Options are to get the wheels refurbished (about £125 a wheel) or replace them - the only thing is, with diamond cut wheels you can only refurbish them once, since each time this is done the process actually scrapes away the surface of the metal to give the shiny new face - and any more than once can limit the strength of the alloy.

Cheers