Download 2001 Mercedes-Benz C320 Spark Plugs Repair Manual – Step 1. Wait for the engine to cool down and gather listed materials. Working on a hot engine is incred- ibly dumb. Step 2. Open the hood and remove the front panel and airbox. (Fig. 1.) Step 3. Protect the air intake with a cover (I used aluminum foil. (Fig. 2.) Fig. 1. Engine all assembled Step 4. Locate the spark plugs. This engine has six-cylindars and twelve spark plugs (six on each side). Select one side to do at a time. Step 5. Starting with the spark plug furthest from the firewall, remove the electrical plug and unscrew unit from the engine using the T-25 Torx bit. Use the magnet to ensure the screw is not dropped into the engine. (Fig. 3.) Step 6. Spray the spark plug boots with WD-40 to loosen them for removal. Wait a few minutes to allow solvent to penetrate. Step 7. Use the 17 mm wrench to pry the boot off from the spark plug. This is the biggest pain in the ass. Try to loosen the boot by turning the boot using your hand. Be careful not to damage or crimp the boot if using the pliers.