I wasn't trying to hammer anyone. I too have a 300E (1989) that burns very little oil. My original question concerned my Dad's recently purchased 300E and my comments about inferior materials were based on a couple of entries by Benzmac which I will cut and paste below.
"The valve stem seal problems were truly valve guide problems that Mercedes has attempted to correct with new/improved valve stem seals. This never worked; the only true way to repair the M103 engine with an oil consumption problem due to valve train problems is to replace all the valve guides - a.k.a valve job. This typically runs between $1,500 and $2,300 and is a MUST if this engine has not had this repair."
"This car will most likely need a valve job to cure. The problem is that the old valve guides where made of a very soft alloy. The new ones are updated and last a good long time. When the car sits, the oil drys off of the parts and when resarted it takes a while for oil to hit those parts."
I guess the real question here is why some cars have problems and some don't when it sounds like they all had the soft alloy guides??
My Dad has all the service records for his car and the oil changes were indeed frequent.
He is taking the car to the Benz dealer today to confirm the diagnosis. I would not expect the dealer to make repairs based on the diagnosis of another shop.