When I first started the car this morning it started making that sound. Then everytime I go somewhere and let the car sit (not running) for around 30 min, the next time I start the car the sound comes back until it basically warms up again. I did not change the viscosity, its still 5w-30. I am thinking about going back to the oil I was using before maybe another oil change with the old oil might do it, what do you think??