Knocking My nephew drove the car and added 12 quarts of oil because the oil light came on. Now it runs but knocks loudly from the top side. Doesn't sound like rods or mains, more like valve train. I will drain off 7 quarts and see if it goes away. What could have happend to it by running it with an extra 7 quarts of oil? Kids are amazingly stupid.

Sir it seem that you see the nearest autorised dealer or service centre for problem such as: 1. Head Decarbonizing 2. Oil chamber Oil sump filter for choke-up or jam need cleaning or replacement. 3. see for proper igniting of spark from the spark plug good supply of current from ignition coil, 4. check for spark plug's 5. Proper fuel supply & good firing  as you mention your car problem that must be likely to be that the engine head system need to get decarbonized, the oil sump oil filter need to get clean-up for sluggage  if any more quaries you can contact me soon.. till then keep on smiling, happy motoring, safer driving, keep your sweet heart clean & tidy see you soon sir..!