Hello all! I just registered but have been lurking around this board for about 6 months. First off, let me just say that I have gained a great deal of knowledge from all of your posts. Secondly I just wanted to chime in about Mobil 1 making engines more noisy. I have used the 5w30 in two vehicles, a 95 Honda civic and a 98 Ford ranger. In both vehicles it made the engines quite a bit louder. I switched the Honda to Havoline 5w30 and The Ford to Amsoil 5w30, and both got quieter and smoother. Also the Mobil 1 got much too dark in my opinion for only 3-4k miles. Just my 2 cents!