Further to Tom’s research and our discussion, the following applies:

  • filling over 9 quarts is useless because the oil will be ejected
  • you can still start a journey at 6 quarts or above (following the logic that after a ‘full-tank-flight’ flight you will still be above the required minima)
  • absolute minimum for the engine’s health is 4 quarts
  • w100 (the standard oil) can be mixed with w80

So, let us:

  • add a quart when at 8 quarts or below
  • make a note in the logbook of the oil available in the engine
  • make sure an oil reserve is available in the front baggage compartment

Further info about the ‘myths of oil’ can be found here.