My 2001 benz did this this season for a couple of cold mornings. FWIW run some marvel mysteriol for 5 minutes before you change the oil...seemed to help my w203 benz....c320 160K miles. Those tolerances are important. you may also want to try hy-per lube.
It's great stuff - its imported and relabeled from here....
careful on upping viscosity..as to what you are running now... jumping up too much may cause problems with the oil reaching the needed areas.
I went from 10w40/10w30 to 15w50...plan on running synth vr-1 20w50 in the summer do to machine age...my mechanic says its a good idea at the mileage and loads I have.