From the day I bought this 2006 Roadster Limited I thought I was fighting a pesky oil drain plug leak. Come to find out it was the oil level sensor all along that I didn't even know was just above the drain plug. This thread is how I went about the repair based on the service manual instructions. Please review the pictures before starting. It will not allow me to upload my videos.

After jacking up the front of the car remove the Splash Shield by removing the front bumper guard pin and the 4 #8 bolts. Using a #13 socket remove the drain plug to drain the oil. To remove the lower oil pan first remove the passenger side Splash Pan Guard (see pic) by removing the 2 #8 screws (it only comes out one way and is tight). In front of the sensor electrical connection there is a cable you can detach from the 2 holders and push up out of the way to disconnect the electrical connector by depressing the lock tab on the right top. Next you will remove 14 #E-10 bolts, 2 from the transmission cooling lines mounts and 12 from the lower pan (leave 2 in loose to catch the pan when it drops). There are a total of 18 #E-10 bolts in 4 different lengths on this project. Keep careful track of them for re-installation. Now you can use the stubby flat screw driver (or two) to wedge the lower pan from the upper pan by carefully driving into the two slots shown in video on the drain plug side of the pan. It does not come off easy. At times you may think you are going to brake something and the pan will flex. On the opposite side of the pan there are 2 tabs that appear to be able to wedge something between them (see pic) I chose to stay away from these as if you were to brake one off it could be a serious issue. As it begins to separate you can use other tools to wedge it down but be careful not the scratch the mating surface. Once loose remove the pan and be aware you will still have oil dripping from the engine. After removal you will see the level sensors two parts connected by a hose. The hose has wires in it. They stay together as one piece. The electrical side inserts upward through a hole and is sealed with an o-ring. The sensor side is mounted and free standing in the upper area. the 4 #E-10 bolts that secure them are 2 different lengths (make a note). Remove the sensor and then clean up both pan surfaces for reinstalling. Install the new level sensor after cleaning the electrical side hole and coating the o-ring with oil. Then torque the 4 bolts to 7 ft lbs. When cleaning the pan surfaces check to make sure there are no scratches from the removal and if there are clean them up carefully with a flat jewelers file. Reconnect the electrical to the sensor and when ready apply the gasket maker to the lower pan only (see picture). I did not do this to mine but I recommend you go around each of the bolt holes as well even though they are closed off from the pan and will not leak but if you are off a little when setting the pan in place and have to slide it, it will provide you with more sealing surface. The factory calls for Loctite 5900 sealant that's not sold in most auto part stores. I ended up using Permatex Ultra Black because I was not in a hurry. It requires a 24 hour cure time. Permatex the Right Stuff Black will cure in 90 minutes if you are in a hurry. For both, the instruction are to hand tighten the bolts until the sealant starts to squeeze out then wait for 1 hour before torquing the bolts to 10 ft lbs. You can then reconnect the 2 transmission cooling lines and torque them to 7 ft lbs. Install the drain plug with a new seal washer and torque it to 22 ft lbs. Reinstall the side panel with the #8 box end wrench (hope you have small hands) and fill her up with oil after the cure time has passed. I ran it and let it come up to temp while still jacked up to make sure there are no leaks. Then I reinstalled the Splash shield and took it for a good drive and then checked for leaks again. One note I did not disconnect the battery for this repair as the sensing system is de-energized when the ignition is off. Do not turn the ignition on when the sensor is disconnect as you may get a code. I recommend you review the pictures before starting. The Mercedes OEM sensor is part number A2759050000 and runs about $220 to $250. Yes there are cheep after market ones and be aware some of them do not come with the o-ring but I recommend the OEM if for any other reason you do not want to do this twice.