paul289

I have a non-PI 4.6 that I replaced intake gaskets on last weekend, and I noticed that the #1 cylinder had thin, brown, deposits on it (see picture), while the rest of the ports were just carbon caked. I was changing the intake gaskets because I had noticed coolant on the #1 spark plug boot, and thought that it must have been coming from the coolant crossover. There was also occasionally some coolant that came out of the exhaust if the truck sat a long time. So I figured that a leaky intake gasket could have caused that, especially if it was leaking into the cylinder.

Would coolant "clean" the intake port like that or was it likely something else, and would seafoam be beneficial or harmful at that level of deposits?