Don't dare do this without doing a valve job. Most of the oil is being consumed by the enigne through the valve guides. I know this from years of servicing these.
It will bring the price up a little, but if you are to keep the car, do the job right and you will be happy.
Thanks

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Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS