After cleaning out the block with a hose, I recovered at least 1.5 cups of "rusty sand and gravel" out of each side of the engine block behind the freeze plugs. I'm stunned this engine didn't overheat and cook itself. Then I removed the oil pump and found a lot of debris clogging the pick up tube. I would like to know what this stuff is. It's chunks of hard black plastic (almost like gravel). The chunks of clear plastic teeth are a mystery too. There was so much sludge in the bottom of the oil pan surrounding the pick up screen. It was like chocolate jello. When I drained the oil, it would stay in there. With the screen clogged and the sludge smothering the pick up tube, it's a miracle the engine didn't seize long ago. The timing chain was loose, so I changed it. I ordered a new oil pump/screen. Sometimes you don't know how bad the inside of an engine is.
