See..and last summer when I was working on heat issues I had that housing off many times. Paper was merely getting in the way. Guess...I'm off to my next idea that I've been tossing around as well. The double gasket.

Ohhhh Machinst Buddy Dave!!!

Actually dissimilar metals can cause corrosion through electrolysis and Galvanic corrosion especially when road salt and other chemicals are introduced into the mix. Not saying that this would happen between the T-stat housing and the lower intake but maybe different metals were used in different years?