Upon driving 400 miles with a trailer full of furniture the car used about 3-4 quarts of oil. When it was changed it was dark sludge. Had oil system flush and changed oil. What could be th cause of theoil use?
To use that much in 400 miles, I would think it is leaking badly. If there exhaust wasn't blue, it has to be leaking or getting into the cooling system. If it was burning oil, you wouldn't have been able to see behind you.