Widgetman

I have two rather old Mercedes sedans. One is a 1989 190E and the other is a 1997 E300D. I love these cars. I do have one perplexing issue with my E300D. It runs perfectly and has really low miles for the year at 115,000. The issue is that it uses a lot of motor oil, about a quart every 110 miles. I did have some leaks but those have been taken care of. Still, it is using that much oil. I put a new OEM differential pressure valve on the PCV system but that had little effect on the oil loss. Any advise from the diesel experts out there?