Was the oil filled to the proper level when it was changed? If it was short filled, then it may seem to be consuming more oil than it actually is. The nominal refill quantity is about 6.3 quarts, but if you jack up the right rear to tilt the oil pan to drain as much as possible like I do it will take about 6.5 quarts.

Do an oil consumption test. Wait for the light to come on, then add a carefully measured HALF quart. Wait for the light to come on again and add another half quart and continue the sequence, recording the odometer reading at each addition.

You need at least 4-5 data points that show consistent mileage between half-quart additions so you can compute true oil consumption. Also check for significant oil leaks.

Valve stem seals are a common cause of oil consumption on these inline sixes, but I don't think it's worth renewing them until consumption gets down to 1000 miles per quart or less, depending on how long you plan to keep the car. If it's a "keeper", new valve stem seals now if consumption is less than 1500 miles per quart might be a good idea.

When new, my car consumed about a quart per 2000 miles, which was more than double the rate of the '84 2.3 it replaced. Mercedes upgraded the valve stem seals with better materials circa 1990, and they agreed to install the improved seals, but I waited until just prior to the end of the warranty period (just under 50K circa late '91) to have them changed. About the time I was ready, the head gasket started seeping coolant on the exhaust side, so they ended up rebuilding the entire head - all new guides, new exhaust valves, and, of course, the latest stem seals.

After the refresh it still consumed a quart about every 2000 miles and has probably increased a little since then.

Duke