Leaks from the timing chain cover is also a common problem on the M103 and you may have had the problem. You will usually find oil on the front anti-roll bar and on the encapsulation panel below the front of the engine.
However, you also have a bad head gasket if you have oil in the coolant and down the rear of the engine on the passenger side.
I had both problems and had symptoms as described in both cases above. When the head gasket is replaced, you automatically get the timing chain cover leak fixed in the process.