The 345 Hemi is Dodge's mid-size V8 engine, found in Chargers from 2005 onward

The 345 Hemi engine is a 5.7-liter V8 that Dodge installed in Chargers starting with the 2005 model year. The "345" refers to its cubic-inch displacement (345 cubic inches equals roughly 5.7 liters). This engine produces between 370 and 375 horsepower depending on the model year and transmission, with torque ranging from 405 to 410 pound-feet. It replaced Dodge's earlier V8 options and became the standard high-performance engine for the Charger lineup.

The 345 Hemi uses Hemispherical combustion chambers — a design that allows the intake and exhaust valves to sit at wider angles, which improves airflow and combustion efficiency. This design is why Dodge calls it a "Hemi" engine. The engine also features variable valve timing and cylinder deactivation on some model years, which shuts down four cylinders during light driving to reduce fuel consumption.

Key Takeaways

  • The 345 Hemi is a 5.7-liter V8 engine that produces 370 to 375 horsepower and is found in Dodge Chargers from 2005 to present.
  • Hemispherical combustion chamber design improves airflow and allows the engine to burn fuel more efficiently than conventional chamber designs.
  • Many 345 Hemi models include cylinder deactivation technology that disables four cylinders during highway cruising to lower fuel consumption.
  • Fuel economy for a 345 Hemi Charger typically ranges from 16 to 20 miles per gallon depending on driving conditions and transmission type.
  • The 345 Hemi requires regular maintenance including oil changes every 10,000 miles and spark plug replacement every 30,000 miles.

Fuel Economy and Emissions Performance

A Charger with the 345 Hemi engine typically achieves 16 to 20 miles per gallon combined, depending on whether it has an automatic or manual transmission and how the vehicle is driven. Automatic-transmission models generally perform better on the highway, while manual models tend to see slightly lower overall fuel economy. City driving produces lower mileage than highway driving because the engine runs at higher RPMs and the cylinder deactivation system cannot engage as effectively in stop-and-go traffic.

The 345 Hemi meets emissions standards for its model year through a combination of technologies: the hemispherical chamber design itself, the variable valve timing system, and a three-way catalytic converter. Older 345 Hemi engines (2005–2007) produce higher emissions than newer ones because emissions regulations tightened after 2007. If you are checking emissions compliance for a specific model year, the year of manufacture matters significantly.

Maintenance Requirements and Service Intervals

The 345 Hemi requires an oil change every 10,000 miles using the oil grade specified in your owner's manual — typically 5W-20 or 10W-30 depending on model year. Spark plugs should be replaced every 30,000 miles. The engine uses eight spark plugs (one per cylinder), so a full replacement is a larger job than in smaller engines, though many owners handle it themselves.

Coolant flushes are recommended every 30,000 miles or every three years, whichever comes first. The transmission fluid in automatic Chargers should be checked at each oil change and replaced according to the transmission manufacturer's schedule — usually every 60,000 to 100,000 miles. Air filters should be inspected every 15,000 miles and replaced when they appear dirty. Fuel filters on 345 Hemi models are typically internal to the fuel pump assembly and do not require routine replacement unless the fuel pump itself fails.

Common Issues and Reliability Concerns

The 345 Hemi is generally considered reliable, but several issues appear more frequently in certain model years. Early 2005–2007 models occasionally experience valve cover gasket leaks, which cause oil to seep onto the engine block. These leaks are not catastrophic but should be addressed to prevent oil from accumulating on hot engine parts. Replacement gaskets are inexpensive, though labor costs vary depending on whether you use a dealer or independent mechanic.

Some 345 Hemi engines develop carbon buildup on the intake valves over time, particularly in models without direct fuel injection. This buildup can cause rough idling or hesitation during acceleration. Professional fuel system cleaning can address this, though the condition is not common enough to be considered a widespread defect. Cylinder deactivation systems on newer models occasionally malfunction, causing the check engine light to illuminate; this usually requires a dealer diagnostic to identify which solenoid or sensor has failed.

Comparison to Other Dodge V8 Engines

Before the 345 Hemi, Dodge offered the 360 cubic-inch V8 (5.9-liter) in Chargers, which produced similar horsepower but consumed more fuel and ran hotter. The 345 Hemi improved on that design by producing comparable power with better thermal efficiency. After 2014, Dodge introduced the 370 Hemi (6.4-liter) as an optional upgrade in some Charger models, which produces 485 horsepower but with lower fuel economy.

The 345 Hemi sits between the base V6 engine (which produces around 250 horsepower) and the larger 370 Hemi. For drivers seeking a balance between performance and fuel economy, the 345 Hemi remains the middle ground. It is more powerful than the V6 but less thirsty than the 370 Hemi, and replacement parts and service are widely available because the engine has been in production for nearly two decades.

Understanding Hemi Technology and Why It Matters

The hemispherical combustion chamber design dates back decades but was revived by Dodge in 2003 as a marketing and engineering strategy. The shape allows intake valves and exhaust valves to open at wider angles relative to each other, which reduces turbulence and allows fuel and air to mix more completely before ignition. This more complete combustion produces more power from the same amount of fuel compared to conventional wedge-shaped chambers.

The trade-off is that hemispherical chambers are more complex to manufacture and require more sophisticated valve train components. However, the improved efficiency and power output justify the added cost for performance-oriented buyers. The 345 Hemi's Hemi design is one reason it became popular in the Charger — it delivered V8 performance that felt noticeably stronger than the previous generation's engines, even though horsepower numbers were similar.

Frequently Asked Questions

How much horsepower does a 345 Hemi actually produce?

The 345 Hemi produces 370 to 375 horsepower depending on the model year and transmission type. 2005–2008 models produce 370 horsepower, while 2009 and later models produce 375 horsepower. Automatic and manual transmissions produce the same horsepower, though they may differ slightly in how that power is delivered to the wheels.

Can I improve fuel economy in a 345 Hemi Charger?

Fuel economy depends primarily on driving habits and maintenance. Keeping tire pressure at the manufacturer's recommended PSI, changing the air filter regularly, and avoiding aggressive acceleration all help. Some owners report modest improvements by using premium fuel, though the 345 Hemi is designed to run on regular 87-octane fuel. Aftermarket intake or exhaust systems do not meaningfully improve fuel economy.

Is the 345 Hemi engine still being produced?

Yes, the 345 Hemi remains in production in Dodge Chargers and other Dodge vehicles. However, Dodge announced that the Charger will be discontinued after the 2023 model year and replaced with an electric vehicle. Existing 345 Hemi Chargers will continue to be serviced at Dodge dealers, and parts will remain available through aftermarket suppliers for many years.

What is the difference between the 345 Hemi and the 370 Hemi?

The 370 Hemi is a 6.4-liter engine that produces 485 horsepower, compared to the 345 Hemi's 375 horsepower. The 370 Hemi consumes more fuel (typically 14 to 18 miles per gallon combined) and generates more heat, requiring a more robust cooling system. The 345 Hemi is the standard V8 in most Chargers, while the 370 Hemi is an optional upgrade for buyers who prioritize maximum performance.

Do I need to use premium fuel in a 345 Hemi?

No, the 345 Hemi is designed to run on regular 87-octane fuel. Dodge does not recommend premium fuel, and using it will not improve performance or fuel economy. Some owners use premium occasionally during hot weather to prevent pinging, but it is not necessary for normal operation.