Daehawk

I dont really notice stuff in it when I look in but I went to have it cold tested and the cap had some kinda brown stuff on it. When I wiped it off it kept it's shape. It felt almost like cork. It was soft and a little slimy. Has someone put stopleak or something in it? There are no leaks I can find.

warthogdriver

When i did my lower manifold on my blazer i had a ton of sludge in the ports as well as the factory rad i replaced. I had used stop leak at one time as well. It may be stop leak in yours. I know after the manifold job i flushed it several times to get it all clear...been great since.