Now serious question time!!

DMAN302

My mom says thanks for the pearl necklace.
Nov 8, 2003
2,120
2
59
windsor, Canada
My car is being stored for the winter in my unheated garage, cold but dry. Now all aluminum items under the hood have been nicely polished and was worth every hour of sanding and polishing. Problem is I have noticed certain alum cast items like the powersteering pump bracket and other little items are oxidizing (spelling???) very quickly, while other parts have not, and have to be cleaned with aluminum polish weekly or it becomes ruff and foggy(for lack of better term). Tell me now what is the cause and if available the method to prevent this. Thank you for your time,
Derek.