Jm123

Afternoon all,We bought a second used x3 three days ago and the coolant light flashed up this morning so I went bought some. I unscrewed the cap and noticed a whole load of frothy brown stuff at the top which I'm pretty sure is oil. Also, it didn't take that much coolant in either which has made my concerns even greater.Has anyone any ideas on this or, anywhere else I can look to double check any problems?Thanks in advance!