I asked my in-house mechanically inclined all around fix-it guy for help answering this one. This was his response, "It could be the oil journals are plugged and starving the engine of oil, which could lead to major engine problems. This isn't something to dink around with. Take it to a good mechanic that you trust."
Bob's a dyed-in-the-wool do it yourselfer. He tears apart and fixes all sorts of things, both RV related and otherwise. For him to say that it needs to see a professional mechanic, well, I'd believe him.