1. Open the hood of your Mercedes C280, and unscrew the oil cap.
2. Locate the plastic panel beneath the engine. This panel needs to be removed to gain access to the oil pan drain nut, and will require an 8 mm socket on a ratchet. There will be four bolts. Unscrew them in a counterclockwise direction and remove the plastic cover.
3. Place your oil pan beneath the oil pan drain nut.
4. Remove the drain nut with your 13 mm socket and ratchet, also turning in a counterclockwise direction. Allow the used oil to drain into the oil pan.
5. Locate the oil filter which will be on the drivers side near the rear of the engine.
6. Attach your socket oil filter wrench and carefully unscrew the cartridge. The cartridge will drop once unscrewed, and along with it will come the filter medium along with o-rings and a gasket. These can be discarded, but the filtering medium can be recycled.
7. Place the new o-rings in place onto the cartridge along with the gasket. Take a new filter medium from your kit and place it inside the cartridge, then carefully screw it back into place in a clockwise direction. Tighten it gently with the socket oil filter wrench.
8. Replace the drain plug and also the plastic covering panel. Pull the drain pan out from beneath the car and recycle the used oil at any automotive service station or hardware store.
9. Pour 7 quarts of new motor oil into the oil filler on the top of the engine, screw on the oil filler cap and close the hood.