About 4 months ago, sorry if this is a repeat, but I cant recall, my motor starting "clicking" at start up and for about 10 minutes, always between 1500 and 2000 RPM. Rev it up or down and it goes away. From my old Chevy days, it sounded to me like bad main bearings. Dealer replaced some valve train parts, cant recall which, car is in the shop so I cant look. Anyway, the next day the clicking is still there. So today he says he thinks it's the oil pump and ordered one. Anyone have this kind of problem? If so how was it fixed. It sounds like marbles in a can.