The 2004 Nissan Altima offered two engine choices depending on trim: a 2.5-liter inline-four (QR25DE) and a 3.5-liter V6 (VQ35DE). The four-cylinder models aimed for efficiency, while the V6 delivered stronger performance. Power figures varied by configuration, with the four-cylinder typically around 165–175 horsepower and the V6 around 240–260 horsepower.
Engine options for the 2004 Altima
The 2004 Altima's engine lineup consisted of two powerplants that could be found across different trims and configurations.
- 2.5-liter QR25DE inline-four — a compact, efficient engine used on base and mid-range models, producing roughly 165–175 horsepower and about 170 lb-ft of torque.
- 3.5-liter V6 (VQ35DE) — a larger engine used on higher trims for stronger acceleration, delivering around 240–260 horsepower and about 250–260 lb-ft of torque.
In practice, the 4-cylinder was more common on entry-level Altimas, while the V6 was paired with higher-end trims for buyers seeking extra performance.
Engine codes and identification
Car enthusiasts and service guides refer to the engines by their Nissan designations, which helps with parts, repairs, and compatibility.
- QR25DE — the 2.5-liter inline-four used in the Altima starting in the early 2000s.
- VQ35DE — the 3.5-liter V6 engine used in the Altima and other Nissan performance lines.
Knowing these codes can help you verify the engine when buying a used 2004 Altima and ensure you order the correct parts.
Performance and maintenance considerations
Power output and fuel economy varied by engine, trim, and transmission. The 4-cylinder typically offered better fuel efficiency, while the V6 provided more confident acceleration. Maintenance requirements also differed between the two powertrains, including oil change intervals, cooling system care, and belt/chain considerations.
Summary: The 2004 Nissan Altima was offered with two engines—the 2.5L QR25DE inline-four and the 3.5L VQ35DE V6. Your exact setup depended on the trim, with the four-cylinder leaning toward efficiency and the V6 toward performance. Always verify the engine by checking the VIN and door sticker.