A little update on the black coolant. I'm in the process of replacing almost all of the cooling system, so once again I had to drain the coolant. There was absolutely no sign of oil or any separation between the coolant and other aqueous solutions. I'm either guessing the black colour was from bad dye or from the water pump having grease in and around the bearings, and when it went out the grease got into the coolant. <- Just a complete guess, but it seems that oil is not the culprit in the black coolant mystery. |