Chances are that nothing is wrong. MB's oil pressure gauge is more like an idiot light than a gauge (on all models except V8s). The actual engine oil pressure probably runs from about 3bar (around 45psi) at idle to about 6-7 bar at higher rpms (I'm guessing as I haven't tested the 103 motor-they never have oil pressure problems).
Very early MBs like 190SLs had full range guages and MB got tired of explaning the variety of reasons for 10-20% pressure changes, so they wiped out the top of the range/gauge.
V8 oil pumps work differently. They get as low as a single bar at idle.
[Edited by stevebfl on 03-24-2001 at 11:31 PM]
Bosch Master, ASE Master, L1
33 years MB technician