So I went to change the valve cover gaskets because had a small leak, when I removed the valve covers discovered sludge bulit up in some locations 1/4 inch thick. If it looks like this under the valve covers, can't picture what it looks like inside the engine. I bought the truck with 56,000 miles and immediatly switched to moble 1 oil. I am wondering what I can do to dissolve the sludge in th engine without causing damage. I don't want to clug up any openings by loosing up the sludge. I am wondering if there is any product that will completely dissolve sludge small enough to pass small openings and flush out the drain plug. Anybody have any suggestions?