Dear Doctor: I own a 2008 Dodge Charger with the Hemi engine with 18,000 miles on the odometer. I change the oil every five months with synthetic oil and quality filters. The owner’s manual requires that the spark plugs (16) be changed every 30,000 miles or three years. This will cost $500. I know that many cars now have plugs that are good for 100,000 miles. Are these also available for the Hemi? George
Dear George: I do not recommend or believe in the 100,000-mile spark plug replacement. I have seen too many spark plugs rot, blow out, and as well, I’ve seen stripped and torn out heli coils in aluminum cylinder heads. I recommend you replace the spark plugs with the original brand and type every three years in Snow Belt areas or 40,000 miles. Sun Belt areas were rust is not a problem can go five years or 60,000 miles. Always use an anti-seize compound on the tread and die-electric grease on the wires before putting the wire back on the spark plug.