My car makes this noise like an intermittent knocking sound on the left side of the engine. It happens at idle with a warm engine. A kid told me at a saab event that my oil was too thin and the bearings were knocking because of low oil pressure, so I threw in a quart 25w-50 into my 5w-30(temporarily) He convinced me to buy Voll-synthese so that will be here tomorrow. But it still makes that sound even with a whole quart of thick oil in there. AHH not my bearings I hate to drive on that but I work 50 miles away! Anyone thinking anything please respond.