2004 Hyundai Sonata Owner's Manual - Page 168

6- 10 DO-IT-YOURSELF MAINTENANCE G060C04Y-AAT Changing the Spark Plugs 3. To remove the spark plug cable, pull straight up on the insulated connector, not the cable. Pulling on the cable may damage the carbon core conductor. 6. To install the new spark plug, guide the socket down over the spark plug, being careful not to damage the ceramic insulator. G060C01O You will find it easier to change spark plugs if the engine is cold. Always change one spark plug at a time. This helps avoid getting the wires mixed up. 1. Remove the center (2.4 L) cover on the engine rocker cover. G060C03O G060C02O NOTE: Spark plugs should be tightened to specification. Over-tightening can damage the threads in the aluminum cylinder head. Also, leaving them too loose can cause the spark plug to get very hot and possibly result in damage to the engine. 7. Replace the cable by pushing the insulated connector directly down onto the electrode. Check to be sure it has snapped into place and can't fall off. ! WARNING: NOTE: It is recommended that the spark plugs (For 2.7L Engines) should be changed by an authorized Hyundai dealer. 2. Using a clean cloth, remove any dirt that has accumulated around the base of the spark plug so it cannot fall into the cylinder when the spark plug is removed. It is recommended that the engine be cool or cold when changing the spark plugs. If the engine is hot, you could burn yourself on the insulated connector, the spark plug or the engine itself. 4. When preparing to remove the old spark plug, guide the socket down over the spark plug, being careful not to damage the ceramic insulator. 5. To remove the old spark plug, turn the wrench handle in a counterclockwise direction.