radiator and oil water on 1992 Mercedes-Benz 300E

What does it mean when there is oil water in the radiator tank

It can mean 2 things, it could mean that your head gasket is wearing out or your transmission cooling tank is leaking transmission fluid in to your radiator because there is a crack. Have a good German car shop inspect this.

here are some shops:
thank you will have that checked out a.s.a.p
1 more answer
Blown head gasket