When GM was still in denial that their resurrected Displacement On Demand (IT'S ACTIVE FUEL MANAGEMENT, SALLY!!!!) was a problem I thought their official standard was 1 quart every 1000 miles....pretty sad for what were effectively new vehicles at the time, and disturbing if you figure the average consumer might not check for 3000 to 4000 miles....then you're down 3 to 4 quarts!!