Brian,
Sometime last year in a copy of Road and Track, someone had written in about oil consumption in his Cadillac Northstar engine. The answer was very good.
Basically it said that engines are made on a assembly line , just like cars, there are robotic milling machines that take the various rough castings and machine them. There are minimum and maximum tolerances for each part of the milling and assembly process. As the assembly process goes down the line pieces that exceed these tolerances are regected . The measurements that usually affect oil
consumption for example ( cylinder roundness, cylinder honing, installing valve guides, piston ring fittment , cylinder wall tapper , to name a few ) also have tolerances . Some engines come off the line towards the higher end of these tolerances. These engines may use a little more oil than the next engine in line, but both engines are within specs and should last a long time. Are the engines defective , NO , they still fall within the engineers specifactions. Volvo is not the only manufacture
that the engine uses oil . Just by design, engines as generall , will use oil . No engine , including race engines, are exempt from oil consuption. Customers assume that the oil will last until the next change. Oil level should be checked at least every other tankful of fuel, and topped off accordingly. BTW the Cadillac owner was complaining of a quart every 1,500 miles which according to the article was OK. Hope this helps explain the engine oil question.

Ted
Stillman Volvo