My confession: I have not been very good about checking the oil level in my Taurus for the past 6-9 months. I know it's one of the pillars of car maintenance, but for one reason or another I have been distracted and negligent. Won't get into that now. I did the oil change on the Taurus this afternoon -- 11 months, 7500 miles OCI. Including draining the old oil filter I barely got 4 quarts out of an engine that takes 6 quarts, so I was down about 2 quarts by the end of my OCI. Yes, I should have checked earlier and topped it off but I didn't. What are the consequences of not keeping my car's sump topped off to the proper level? Engine is the Duratec 24 valve 3.0 liter V6.