"A diesel will consume massive quantities of oil before it shows blue smoke."

"you can burn a quart of
oil every five hundred miles without it being visible in the exhaust. "
My 240 is a prime example of how true these statements are... I am burning a quart in less than 250 miles...and you would not notice any soot/smoke if you saw me driving around... my 81td was much "smokier" and only used normal amounts of oil... most smoke from diesels is unburned fuel...'properly' burned oil is almost invisible compared to improperly burned fuel....