Are there documents that say specifically what overfilling the oil to a total of 9.5 quarts will do to a motor?

Am not aware of any documentation available on this subject. Surely you have drained the oil and reset it to the proper level.

It can cause hard starting, slight engine smoke and poor performance. I don't think it will cause any permanent damage if you have reset the level within the normal oil change intervals. I would suggest running a high octane fuel (the highest available at the pump) for at least 2 tank full's and this should help reseat the rings after setting the oil level to the proper specification.

Overfilling the oil Troubleshooting:

  1. Locate and check your oil level with the engine off and parked on a level surface.
  2. Drain if overfilled. If its just a tad (1/8") over, no worries.
  3. Set oil level to correct specifications
  4. Check often to make sure level doesn't increase, if it does you have a different problem altogether.
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