Protecting aluminum engine parts

Move to the southwestern US.

"Johnny" floridly penned in news:3f454738$1_1@mk-nntp-

It doesn't. Rusting is the oxidation process iron goes through on its way back to becoming iron oxide again.

Aluminum is used these days as an "environmentally friendly" substitute to zinc, as a sacrificial anode on iron-based parts. This is the grey coating you find on some unpainted auto parts. It replaced the much cheaper zinc yellow dichromate.

Aluminum is very resistant to corrosion once it develops its oxide coating, which is within a few minutes of exposure of a fresh surface to the atmosphere. However, aluminum does pit and corrode. Salt is the biggest enemy of aluminum. Salt is frequently found in water thrown up from the road, and is dissolved in the air in certain areas. Salt occurs naturally in the earth's surface and becomes mixed with rainwater and runoff.

In any Northern or rainy climate, aluminum will eventually turn to a white dust. How to protect it? Keep water and air away. That means anodizing and painting or a heavy petroleum-based coating, such as Cosmoline. All of this probably too expensive or messy to do for the automakers.

Hah! That's the stuff I had to scrape off the alum. outdoor lamps before painting them! It formed UNDER the paint too, causing it to blister.