Jacob, are you checking the dipstick after starting the engine or right after filling? I pour in 6 quarts, idle for a couple of minutes, then add about another quart to have it settle between the min and max marks. It's the same whether I use the drain plug or Topsider.

Chris, 8 gallons? Are you using the filler cap as a dipstick?

Sixto
95 S420
91 300SE
87 300SDL
83 300SD