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DISCUSSION => Engine + Driveline => Topic started by: highlandmiata on March 29, 2007, 05:40:45 PM

Title: corrosion on intake and valve cover?
Post by: highlandmiata on March 29, 2007, 05:40:45 PM

found a car with just over 100k on the clock. some issues I can live with, but has pretty bad corrosion on the intake manifold and the valve cover. Is this a sign of something bad?

Title: corrosion on intake and valve cover?
Post by: b318isp on March 30, 2007, 03:26:49 AM

What sort of corrosion? Never heard of them being bad - they are aluminium.

Title: corrosion on intake and valve cover?
Post by: shutter on March 30, 2007, 04:31:19 PM

Is it goldish color?  If so, it's like that from the factory.  It tends to get a bit flaky at this age, but nothing to worry about.  It just looks bogus!

Title: corrosion on intake and valve cover?
Post by: highlandmiata on March 30, 2007, 10:54:45 PM

yeah, part of it is goldish and flakey, part of it is white powder. I took the plunge and now own a 91 318is with 103K (guess what color)

Title: corrosion on intake and valve cover?
Post by: sumyungguy on March 30, 2007, 11:28:14 PM

alpinweiß ll??

Title: corrosion on intake and valve cover?
Post by: kowalski on March 31, 2007, 06:10:33 AM

thats not corrosion. they put it on for who know's why. but its like a grease coating. you can take it off with a steam cleaner.

Title: corrosion on intake and valve cover?
Post by: an318is on April 01, 2007, 07:09:05 AM

The yellowish stuff is called Kosmoline, Its basically a protective coating to help the durability and corrosion resistance of the aluminium. Aluminium can corrode if the aluminium oxide layer is broken down and cant regenerate. This will happen at certain PH levels. If youd like to try it put some aluminium in engine decrease, no matter how watered down, a smooth surface will start to pit. There are other factors that influence this too though.

In short i think it was placed there to help protect the aluminium from cleaning with most engine degreasers and also used as a protective coating for scratches and alike.