Did you check the oil level at the beginning of the thousand miles?

If someone other than you changed the oil, it is possible that they added a bit too much. I find that the technicians that change my oil often put a bit too much oil in when filling the car.

I have gotten in the habit of checking all the work that I get done as they often make small errors. And sometimes BIG ones.

BTW - how often do you check your oil, I do mine weekly.

If you are losing coolant, a quart should show.

How's your fuel mileage? Fuel in your oil is a much more likely scenerio IMHO.
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3 8s & 2 7s 740,000 miles total