Did an oil change on my stepdaughters 2000 300m that she just bought. When I started, the dipstick showed a quart low. Drained it, put on a new filter and added 5qts of oil (per the owners manual). Dipstick showing a quart low again after change. Started looking online and found a couple places that say the 2000 3.5L takes 6 quarts. Anyone know for sure what this motor takes? I even went as far as to check the part # on the dipstick to see if it was the wrong stick. Appears to be the right part for the car.

 

The Haynes manual states that the 3.5L engine takes 5.5 quarts, or did in 1997. I don't have a more recent version.