In most modern Chrysler 300 models with long-life spark plugs, you typically replace them around 100,000 miles under normal driving; verify with your owner's manual for your exact engine and year.
The Chrysler 300 has commonly been equipped with the 3.6L Pentastar V6 and the 5.7L Hemi V8, with additional variations offered in certain years. Replacement intervals depend on plug type (iridium/platinum vs. copper) and driving conditions. This article provides guidance on standard intervals, signs of wear, and how to approach replacement, with notes on year-to-year variations up to 2024-2025.
Engine options and plug replacement intervals
While exact numbers come from the owner's manual, here is a practical guide for the two most common engines in recent Chrysler 300 models.
What affects the interval
Several factors influence when you should replace spark plugs, including plug type, driving style, and operating conditions.
- 3.6L Pentastar V6 (most models from about 2011 onward): Many plugs are long-life iridium or platinum, with a typical replacement interval of about 100,000 miles under normal driving.
- 5.7L Hemi V8 (selected models and years): Also commonly equipped with long-life plugs; 100,000 miles is a typical interval when driving under normal conditions.
Note: If your vehicle uses traditional copper plugs or if you drive in severe conditions (towing, frequent short trips, extreme temperatures, or heavy loads), the interval may be shorter—often around 60,000–90,000 miles. Always consult the owner's manual or a Chrysler technician for the exact specification for your year and engine code.
Symptoms that indicate spark plugs may need replacement
Even with long-life plugs, wear can occur sooner in certain operating situations. Watch for these common signs that point to spark plug wear or fouling.
Key indicators
- Rough idle or engine misfires, especially at idle or low speeds
- Decreased fuel economy and reduced engine performance
- Difficulty starting or extended cranking, or trouble starting in cold weather
- Check Engine Light with misfire or ignition-related codes (P0300 series)
- Visible wear or fouling on plugs, or you haven't replaced them at the recommended interval
If you notice any of these symptoms, have the plugs inspected and tested; replacing them is a straightforward maintenance task that can prevent more serious issues. If you’re unsure, a professional diagnosis can help avoid unnecessary work.
Summary
For most Chrysler 300 models equipped with modern long-life spark plugs, plan for replacement around 100,000 miles under normal driving. Confirm the exact interval in your owner's manual, as engine type and plug design vary by year and market. If you drive under severe conditions or use copper plugs, be prepared for more frequent changes. Regularly monitor for signs of wear and address them promptly to maintain performance and fuel efficiency.