I went from a 10W30 to a 5W30 dino oil. It was due for a change. Keep in mind I've put only 5 miles on the car since the head gasket, so it may not be oil, but perhaps a soft contaminant in the valve train that worked loose. I wanted to run the car a bit to trap all the contaminants from the head gasket work before charging it with new oil.
Only a few more things to do before it's ready for summer.
95 E320 Cabriolet, 131K