Denso 4099 Spark Plug

Buyer fitment guide only intended as reference. Please use catalogue search by vehicle to ensure proper fitment.

• DENSO Auto Parts X24ES-U
• DENSO Auto Parts X24ESU
• NAPA Mileage Plus 4099

• 100 percent pre-fired to ensure reliable operation
• Copper core center electrode for superior thermal conductivity
• Developed to meet the demand for improved ignitability, necessary for increased efficiency in emission gas purification and fuel consumption.
• Dual copper and glass seal bonds the center electrode and insulator together for a gas-tight seal.
• Lasts twice as long as conventional plugs
• Unique five-rib insulator reduces flashover and decreases voltage loss
• DENSO€™s patented U-Groove spark plug enables complete combustion by allowing the spark to fill the gap created by the U shape. The ball of fire created in the U-Groove develops a larger and hotter flash front that virtually eliminates excessive fouling and erratic starts caused by poor fuel mixtures. Even DENSO€™s €œstandard€ spark plug is something special. The innovative design that helped to make DENSO spark plugs famous, the U-Groove plug employs a unique, channeled ground electrode designed to generate a larger spark nucleus at the point of ignition. Greater spark energy than ordinary plugs means improved flame travel, producing more complete, consistent, and efficient combustion.