Just as a precaution, when I drained the coolant from the block of my old 500SEL, I purchased two drain plugs in case I strip the ones on the car and have to drill them out or something. You may want to exercise that backup as well.

__________________
1999 Mercedes-Benz S600, 103K miles - garage queen
1988 Mercedes-Benz 560SEL, 89K miles - daily driver
2007 Hyundai Sonata Limited, 31K - daily driver