Open the hood of your vehicle.
Locate the oil dipstick. It is usually a long, thin stick with a yellow or orange handle.
Pull the dipstick out of the engine and wipe it clean with a rag.
Reinsert the dipstick into the engine until it is fully seated.
Pull the dipstick out again and check the oil level. The oil should be between the "Full" and "Add" marks on the dipstick.
If the oil level is low, add enough oil to bring it up to the "Full" mark.
Replace the dipstick and close the hood of your vehicle.
Here are some additional tips for checking the oil in your 2005 Mercedes-Benz:
Make sure the engine is off and has had time to cool down before checking the oil.
Check the oil level regularly, especially before and after long trips.
If you are unsure how to check the oil in your vehicle, consult your owner's manual or a qualified mechanic.