Since Amsoil has changed over to their new formulation which supposedly cleans much better and has 100% protection against LSPI I have noticed that the oil gets far darker and more quickly on the dipstick than before. I suspect it's this increased cleaning ability that is turning the oil dark and I wonder if it will slowly go back to the way it was once it's done cleaning up the engine ?!? Usually I would drive it to 10,000 miles (16,000km) and it would just be turning a light brown at that time and would drain out black. Now it's been 4500 miles (7200km) and it's already that colour. I'm not worried, it's more of an observation but I will be running a UOA to see if it tells anything or if there is something else going on in the engine that might be contributing to it. So far no consumption and no coolant level change so it has to be the new formulation reacting differently I would suspect. Just thought I would share.