Engine Surface Corrosion in 2018 F80?

[Paisano]

Originally Posted by hellokitty

I used some mother’s metal polish and that took care of it. Also polished up the top of the intercooler and it changed to a different shade of color lol... looked like a lot of oxidation built up and it cleaned it up nicely.

Any chance you could post some pictures? I know the metal polish you used, really good for most exhaust tips and such.

[wdskukm3]

I had some of that on my 2015. I just used a 3M scotch brite to clean it up. Remove most of it but not perfect.

[No.401_Speed]

Unless you're big on detailing and keeping the engine looking factory new (like me) then this is not a problem. The aluminum surfaces of your engine will form a layer of oxidization and this layer will then protect the aluminum part from further oxidization. This is a form of corrosion, but not the same as rust which continuously eats away at iron/steel parts that are exposed.

I use one of two solutions:

If you don't care about colour, you can apply WD 40 with a toothbrush and work that into the aluminum surface. This will protect the metal and make it look uniform without the ugly scale effect.

If you want to keep the bright factory shine of the aluminum part, then apply Mother's Mag & Aluminum polish with a rag or toothbrush, work it into the metal and then buff it with a clean cloth.

I used WD 40 on my N52 engine (E-92 328i) and I'll likely apply the same approach to my S55 while using Mother's on the oil filter housing, inter-cooler box and alternator housing.

Here's a before/after shot of my oil filter housing in my 2015 M4. I just purchased it two weeks ago and applied a couple of coats of Mother's using a toothbrush and rag. Still more work to be done but you can see that the "salty" look is gone and all that remains is the oxidization marks that should come out with more polishing (get a polish attachment for your hand drill if you really want to work it clean).

Otherwise, leave it alone. You won't win any prizes for detail, but you also need not worry about those parts rusting away.

[FlyingLow78]

My ‘18 M3 has never seen snow and I have the corrosion on the oil filter housing and alternator. It’s almost 100% a track car these days, so I don’t care. For those of you working to keep the aluminum bright, kudos.