I drive nearly 700 miles a week also and IF I slow down to 65-70 I regularly get 25+ MPG, if I slow down to 60-65 I can easily get another mile or two per gallon, I have seen 28MPG for a 100 or so mile run. I just got done with a 2,000 mile trip yesterday, "drove 80", the computer showed an average speed of 72 and an MPG of 24.4.

I assume you've done an accuracy check? (IOW, fill up, do the tank to either 1/4 or the warning light, re-fill and calculate the actual mileage.) If you're driving alone on flat, well maintained roads without heavy traffic and not hauling anything in back, the numbers are within the realm of reality. If you're loaded up with people, have baggage in the back, are in traffic for any long period or are on poorly maintained, hilly, winding roads, those numbers might be ever so slightly high. Not a lot, mind you! Particularly with a well-maintained car with proper tire pressure and good driving habits.

I do love the diesel!

STP

oil blow-by the turbo at low boost situations (in other words most of the time) on a turbo-diesel engine is normal.

if you remove the intake on any turbo diesel engine you will find that it is always wet, sludged-up a bit. this is from the blow-by. the oil enters the turbo to cool it off and if the turbo is not spinning hard enough it will seep through the bearings and will find its way into the manifold. on the diesel vw cars the oil also leaks outside of the turbo.

if bad enough (worn out turbo) you get the dreaded "run-away" diesel engine - a condition where (especially on automatic tranny vehicle) the engine races at redline and over and cannot be stopped even if you turn off the ignition because the engine is feeding on blown-by engine oil by the turbo. lots of smoke and destroyed engine is usually the result.

consuming some oil in the gl320 is normal.

alex
few cars

How long can a bottle of oil last if you dont open it? I have a case of Mobil 1 synthetic when I had my oil burning Porsche CS and I plan on buying a 2009 320CDI blu tec. The case of oil has been sitting for about one year.

The oil will be fine but it probably is the wrong oil unless it is ESP Formula M that meets the 229.51 spec. With few exceptions, it can only be purchased at the dealership.