This recent thread usually brings up some admonition that the cause of the problem is the lack of frequent changes of anti-freeze. While this may exascerbate the problem, the root cause is something else. Check out http://www.radcapproducts.com/prodinfo.html for a very interesting discussion that should be of real interest to all of us with aluminum engines. Unfortunately, the product they sell won't fit in our header bottles without some modification. However, it is a very interesting bit of information. Dick Ryan VIN 16867 __________________________________________________ Do you Yahoo!? Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop! http://platinum.yahoo.com