Cast Aluminum White Powder Spots

[warrior151]

Ok...I have tried just about everything to clean cast aluminum white powder spots under the hood on my 2005 M3. Brushed and scrubbed with WD-40 with no avail...they just keep coming back!! UGH!

Ok Pros...how do you clean and stop this corrosion? I am at wits end with this!!

Thanks!

DC

[chaotik]

Any pics to understand what this exactly is.... As you found out... WD40 won't do anything for u... It will just hide the spots until it dries out and they reappear.

[forrest@mothers]

White spots on aluminum means an acid of some sort was used on it.

Your best bet will be an aluminum polish.

[warrior151]

Here is a photo of my M3 engine...the white powder dots is what keeps coming back....

I will try the aluminum polish!!

Thank you!
DC

[opie_7afe]

where abouts do you live? i have some of that happening to non aluminum parts,however i live right on water so i know its most likely salt corrosion, basically you would need to clean best as possible and keep it protected, with aluminum the corrosion needs to be removed as it can go below the surface, so need to polish it most likely, on painted steel parts use some polish for paint or remove sand down to bare metal and repaint or replace part. but the aluminum corrosion on valve cover you might need to remove it and if your removing it minds well sand down the cast marks and fully polish it!. or just get it powder coated. it does not effect performance really its just unsightly to keep the stuff down takes alot of care, same reason why people with these highly polished aluminum engines dont drive them much as heat has a good bit to do with it also.

[oldmodman]

Now that you have posted a picture of the problem I am afraid that nothing will eliminate them since they are coming up through the anodizing (or what looks like anodizing, might be some kind of paint).
You will have to remove the parts, have them media blasted and powder coated. I have had to do the exact same refinishing method on marine engines.
Nothing else will eliminate the corrosion coming up through the previous paint, anodize, or whatever coating was used to make those parts look black.

[warrior151]

Thank you Oldmodman...that is what I was afraid of...the car came from NJ but I am in Maryland...not too close to the water. This car needs some TLC and a few mods so I guess I will be upgrading some of the parts inside the engine compartment while I am at!

DC

[opie_7afe]

aah yes maryland/nj really close to salt water,and salt on the roads also, both of those are not good on any part of the car, basically the salt can eat through paint and leave those white dots, aluminum is un protected so it happens faster, salt in the air/water will carry more electrons which in turn will corrode faster then non salted water. so only way to fix is sand,repaint (for painted pieces) and use a stainless wire brush or stainless steel wool(i suggest this as if you dont get all the tiny steel fibers away they can rust and leave staining or even worse depending on location) sorry your car is doing this, another way to prevent it is frequent engine wipe downs(after a deep clean of course) and that will help greatly with the corossion. as i said its happening to my 94 celica as it was a NY car untill about 2005, then came down here untill now. i always try to take something negative and try to turn it into a positive like "my valve cover is corroded man that sucks, on the good side now i can remove it and paint it the color i wanted!". hope this gets worked out for you, might help to browse the bmw forums and see if this is a common issue(no matter of location) or if its due to engine not being cleaned enough to remove salt build up. again good luck and hope i helped provide some information as im the type who likes to make others understand why something is doing what its doing, ive always been questionable of things and wanting to know why it works or how it works. wish there was more data available on how car wax works and such.

[warrior151]

Thank you all for the inputs and suggestions...I see I will have to rub the aluminum often...well until I get tired of it and powder coat or replace some of the parts in the future...let you all know what I come up with!!

Opie_7afe...appreciate the options. I am going to reach out the M3 forum and see who else might be experiencing this...

Later,

DC

[Vegas Transplant]

I need to learn to push away from the keyboard and find something else to do. However, I am in agreement with the earlier prognosis. Forrest hit it right on the head, and the photos, at least from my perspective seem to reiterate Forrests' post.