When to change spark plugs in 5.7 Hemi?

The typical replacement window for a 5.7L Hemi with modern long-life plugs is about 100,000 miles under normal driving. If yours uses copper plugs or you drive in harsh conditions, expect changes sooner, around 30,000–60,000 miles. Always verify the exact interval in the owner's manual for your model year.

Factory guidance and typical practice

Automakers publish schedule recommendations, but real-world replacement often aligns with the type of plug installed and how the vehicle is used. For most late-model 5.7 Hemi engines that come with long-life iridium or platinum plugs, the suggested interval is around 100,000 miles. If the vehicle uses older copper plugs or if you’ve replaced them with non-OEM parts, the interval may be much shorter. Severe service conditions can shave a substantial portion off the life of a plug.

• Long-life plugs (iridium or platinum) are commonly rated for about 100,000 miles in normal use.


• Copper or standard plugs, still used on some configurations, typically require replacement around 30,000–60,000 miles.


• Severe-service driving—frequent short trips, towing or heavy loads, hot climates, or lots of idling—will generally shorten the interval.


• Always consult the owner's manual or a dealer for the exact interval for your model year and plug type.

In practice, many owners align with roughly 100,000 miles for modern long-life plugs, but you should monitor performance and inspect if you notice symptoms or uneven engine behavior.

How driving conditions affect timing

Several operating conditions can influence when spark plugs wear out on a 5.7 Hemi. The following factors commonly push the replacement sooner than the nominal 100k mark.

• Short trips and city driving where the engine doesn’t fully heat up.


• Frequent stop-and-go patterns that increase ignition cycle count.


• Heavy towing, hauling, or sustained high-load driving.


• Extreme temperatures or dusty/high-altitude environments that affect combustion and cooling.


• Poor fuel quality or incorrect octane that can cause pre-ignition or fouling.


• Recent misfires or coating on plugs due to oil/fuel issues or worn ignition coils.

Under these conditions, expect to inspect plugs sooner and consider replacement at 60,000 miles or less depending on symptoms and plugs used.

Signs it's time to replace spark plugs

Be alert for indicators that the spark plugs are nearing the end of their life. The following symptoms can signal you should inspect or replace the plugs.

• Rough or hunting idle, especially at cold start.


• Engine misfires, hesitation, or rough acceleration.


• Reduced fuel economy or loss of power.


• Difficulty starting or a rising number of misfire codes.


• Visible wear or fouling on accessible plugs, or oil/fouling on the plug threads.

If you notice these signs, have a diagnostic check to confirm ignition system health and consider replacing plugs.

What to expect during replacement

Replacing spark plugs on a 5.7 Hemi involves accessing each cylinder’s coil-on-plug arrangement, removing coils, extracting old plugs, and installing new ones with proper torque. If you’re not comfortable, a professional service is recommended.

• Ensure you have the correct replacement plugs for your engine year and plug type (long-life iridium/platinum or copper).


• Disconnect the battery and carefully remove ignition coils to access each plug.


• Install new plugs with the correct torque and verify no cross-threading.


• Reconnect coils, clear any codes, and test drive to confirm smooth operation.

Professional technicians will ensure proper torque, seal, and function across all cylinders and may replace coils if worn during service.

Summary

For most 5.7 Hemi engines, plan for a spark plug replacement around 100,000 miles with modern long-life plugs. If copper plugs were used or you operate under severe driving conditions, expect earlier replacement, sometimes around 30,000–60,000 miles. Always consult your owner's manual and pay attention to signs of wear, such as rough idle or reduced performance. Regular maintenance and using the correct plug type will help maximize performance and fuel economy.

What is the lifespan of a 5.7 Hemi engine?

A 5.7L Hemi engine can last between 200,000 and 300,000 miles or more, with some reaching over 300,000 miles, when properly maintained. Factors like sticking to the maintenance schedule, including regular oil changes and fluid checks, are crucial for longevity. Some owners have reported high mileage with minimal issues, while others have noted specific common problems like exhaust manifold cracks and lifter/cam issues related to the Multi-Displacement System (MDS). 
Factors affecting lifespan

• Regular maintenance: Sticking to the recommended maintenance schedule, including timely oil changes and fluid checks, is the most important factor for extending the engine's life. 
• Driving habits: Consistent driving and avoiding excessive strain can help. Some owners suggest driving in tow/haul mode to prevent the MDS from engaging, which they believe can prevent certain issues over time. 
• Common issues: Be aware of potential problems like exhaust manifold cracks and issues with the lifters and camshaft, which are often linked to the MDS system. Addressing these issues promptly can prevent more significant damage. 

Examples of longevity

• Many owners report high mileage with their 5.7L Hemi engines, with some vehicles reaching over 200,000 to 300,000 miles without major engine problems. 
• One user reported their 2004 Hemi engine was approaching 400,000 miles with no engine problems. 
• Another user's 2010 5.7L Hemi had over 280,000 miles with no issues. 

Rebuilding

• If the engine block and heads are intact, a rebuild can be performed to extend the life of the engine for another 100,000 miles or more. 
• Some owners consider a rebuild a worthwhile investment, especially when compared to buying a new truck. 

When should you change spark plugs in a 5.7 Hemi?

The 5.7L HEMI spark plug change interval varies by model year: replace plugs every 30,000 miles for pre-2014 models, and every 100,000 miles for newer models (2014 and later). The longer interval applies to vehicles using the more durable iridium or platinum spark plugs, which are standard on newer models.
 
You can watch this video to learn how to replace the spark plugs on a 2019-2024 Ram 1500 Hemi E-torque: 1mAmericanTrucks RamYouTube · Mar 6, 2025
Before 2014

• Interval: Every 30,000 miles.
• Reason: These models often used standard nickel plugs which have a shorter lifespan. 

2014 and newer 

• Interval: Every 100,000 miles. 
• Reason: Newer engines typically come equipped with long-lasting iridium or platinum plugs, which are designed for this extended service life. 

What to watch for

• Even with the recommended interval, you should inspect your spark plugs sooner if you notice symptoms of wear. 
• Symptoms of worn spark plugs include:
  • Difficulty starting the vehicle 
  • Rough idling 
  • Engine misfires 
  • Decreased acceleration or sluggishness 
  • Reduced fuel economy 

What is the bad year for the 5.7 Hemi?

The "bad" years for the 5.7 Hemi include 2003-2008 due to a known issue with valve seats dropping, which can cause significant engine damage. Additionally, 2011-2012 model years, particularly in Ram trucks, were notorious for the "Hemi tick," often linked to lifter or camshaft problems.
 
This video explains the common issues with the 5.7L Hemi engine: 58s8020 AutomotiveYouTube · Oct 13, 2022
2003–2008 (Pre-Eagle) 

• Valve seat drop: This is the most significant issue for this period, where valve seats could fall out of the aluminum cylinder heads, leading to engine damage. This is due to the different expansion rates of the steel valve seats and aluminum heads. 

You can watch this video to learn more about how to prevent the valve seat drop issue: 56sMarspeedYouTube · Nov 20, 2020
2009 and later (Eagle) 

• Hemi tick: The 2009 "Eagle" Hemi introduced revisions that brought a new problem: an intermittent ticking noise that can indicate worn lifters and camshafts. 
• Lifter and camshaft failure: The ticking noise is often a precursor to lifter failure, which can seize and cause the camshaft to wear down. This is a costly repair, often running thousands of dollars. 
• Multi-Displacement System (MDS): The MDS system, introduced in 2005, can contribute to engine tick. It deactivates four cylinders during cruising, creating temperature differences that may cause oil flow problems. 
• Specific problematic years: While the issue became more widespread in later years, the 2011 and 2012 models are particularly noted for the "Hemi tick". 

This video shows how to diagnose and address the Hemi tick issue: 57sJack FletcherYouTube · Dec 10, 2022
Other considerations

• Exhaust manifold leaks: This can occur in many model years and may be mistaken for the engine tick. It often sounds like a tick, especially on a cold start, and is caused by broken manifold bolts. 
• Transmission issues: Many 5.7L Hemi vehicles have also had issues with their transmissions, which can lead to costly repairs. 

Do I really need to change my spark plugs at 100,000 miles?

Yes, replacing spark plugs at 100,000 miles is a common and often necessary maintenance task, as many modern vehicles have spark plugs rated to last that long. However, the exact interval depends on your vehicle's make, model, and the type of spark plug installed, so you should always check your owner's manual for the manufacturer's specific recommendation. 
This video explains when to change spark plugs and what happens if you don't: 1mHonest Mechanic ColoradoYouTube · Dec 24, 2023
Why it's important

• Engine performance: Spark plugs that are past their prime can cause rough idling, poor acceleration, and decreased fuel efficiency. 
• Preventing damage: Over time, worn-out plugs can put extra stress on other components, like ignition coils, and may seize in the engine block, making them harder to remove later. 
• Preventative maintenance: Replacing spark plugs is a form of preventative maintenance that can prevent more costly repairs down the line. 

This video explains why it's important to change spark plugs at 100k miles: 52sWhite One Auto, LLCYouTube · May 19, 2021
What to consider

• Owner's manual: Your vehicle's owner's manual is the most reliable source for the correct replacement interval and recommended plug type. 
• Spark plug type: The lifespan of spark plugs varies by material. Iridium plugs are often rated for 100,000 miles or more, while other types like copper or platinum have shorter lifespans. 
• Driving conditions: Severe driving conditions can shorten the life of spark plugs, so your interval may be shorter than recommended if you frequently tow, drive in extreme temperatures, or frequently start and stop.