There are many ways a head gasket can fail, with a variety of symptoms. Since you are just losing coolant, I would address that. A small leak can be hard to find but easy to seal up. Some of these cars can even lose coolant into the windshield washer container.

Yes, I know there might be some coolant in your oil, but I would force the car to prove to me that it had a bad head gasket before I would tear it apart. I would like to have a dollar for every time I thought I had a problem figured out, only to find out I didn't.

__________________
'97 E 300 D