1. Open the hood of the car.
2. Locate the engine oil dipstick. In the C240, the dipstick is located on the driver's side of the engine, near the back. It is a long, thin metal rod with a yellow handle.
3. Pull the dipstick out of the engine and wipe it clean with a rag.
4. Reinsert the dipstick into the engine until it is fully seated.
5. Pull the dipstick out again and check the oil level. The oil should be between the "Full" and "Add" marks on the dipstick.
