Mmr1

2013 glk 350 (gasoline) , 37,000 miles. I just bought it certified used at MB dealer 2 weeks ago. It's had 3 oil changes at Mercedes by the previous owner (by the car fax). MB just changed oil at 37000 again for me. In the morning it's overfilled by more than 1/2qt. It's past the red plastic and hitting the wire. I drive it and check it in 3 min and it's at the bottom. 30 minutes later it shows 1/2 full. 1-2 hours later it's overfilled again. Where is the oil holding? What caused this? What's the fix? I've only seen old Junkers hold oil in the cylinder heads from sludged oil journals. Also at startup in the AM for a few seconds you hear it's starved of oil. Also warm and idling with hood open there is a fairly rapid clicking from the top of the motor, it's about double the speed of a bearing noise. MB checked out the noise and said its normal on that motor , (I think no noise is normal) . So if it was low a qt when previous owner checked oil after it sat for hours, I believe it could have been running 2qt low. What's going on with my new used MB, it seems in excellent shape otherwise.