I just went and really looked at the coolant. . Fairly certain it's motor oil in there. Is the oil cooler on these cars like the ones I'm familiar with on heavy diesel motors. Basicly brass tube that coolant passes thru and on the opposite side is the motor oil. If we ever have oil in the coolant that's the first thing we change. Then put water and dawn dish soap in the radiator and run it drain it and do it again till its clean.