What kind of engine is in the Lexus rx400h?
In brief, the Lexus RX 400h combines a 3.3-liter V6 gasoline engine with electric motors under Toyota's Hybrid Synergy Drive to power the vehicle.
The following sections explain the engine and the hybrid system in more detail, including how the components work together to deliver power, efficiency, and all-wheel capability.
Engine and Hybrid Architecture
The RX 400h’s powertrain centers on a traditional gasoline V6 augmented by an electric drive system. The core components are:
- Gasoline engine: a 3.3-liter V6 internal-combustion engine
- Hybrid electric motors: two electric motors integrated into the system (one on the front axle and one for the rear axle)
- Hybrid synergy drive: a planetary gearset and control electronics that blend output from the gas engine and electric motors
- Transmission: a continuously variable-type hybrid transaxle optimized for seamless power delivery
These elements work together to allow the RX 400h to operate on electric power at low speeds, recharge the battery during braking, and switch to the gasoline engine as needed for sustained highway driving or higher power demands.
Hybrid drivetrain layout
Unlike a conventional front- or rear-wheel-drive setup, the RX 400h uses a split-power architecture. The gas engine primarily drives the front wheels, while a dedicated rear electric motor supplies torque to the rear axle. This arrangement enables all-wheel drive (AWD) without a traditional driveshaft connecting both ends of the vehicle, and it allows the vehicle to run on electric power for short periods and at low speeds.
Performance and Efficiency
The RX 400h delivers a combined system output that Lexus characterized as around 268 horsepower, with the gasoline V6 providing the core propulsion and the electric motors delivering supplemental torque, especially at lower speeds. This hybrid setup was designed to offer better real-world fuel efficiency than a conventional V6 SUV of similar size, particularly in city driving, while still providing strong highway capability when needed.
EPA ratings and real-world efficiency varied by model year and driving conditions, but the RX 400h was generally positioned as a mid-20s to mid-20s range in combined miles-per-gallon across standards of its era. The model also established Lexus’s path toward later, more refined hybrid SUVs such as the RX 450h (later renamed RX 450h) that followed the RX 400h’s formula with updated technology.
Context and Legacy
The RX 400h was Lexus’s first dedicated hybrid SUV and a stepping-stone toward the brand’s broader hybrid lineup. Produced roughly from 2005 to 2009, it laid groundwork for subsequent generations that improved on battery chemistry, electrical architecture, and overall efficiency while expanding to larger and more capable hybrid systems.
Today, the RX family continues with newer hybrid and plug-in variants, but the RX 400h remains notable as the original blend of a mid-size luxury SUV with a dedicated hybrid drivetrain.
Summary
The Lexus RX 400h uses a 3.3-liter V6 gasoline engine paired with two electric motors within Toyota’s Hybrid Synergy Drive. The system blends power from the gasoline engine and electric motors through a hybrid transaxle to drive the front and rear wheels, delivering a combined output around 268 horsepower and offering improved efficiency for its era while maintaining SUV practicality and all-wheel capability.
In the broader context, the RX 400h represented an important early step in Lexus’s hybrid strategy, a template that informed later, more advanced hybrid SUVs in the lineup.
For current buyers and enthusiasts, understanding this configuration helps compare the RX 400h’s blend of performance and efficiency with later hybrid models and with non-hybrid competitors in its class.
What engine is in a Lexus RX400h?
The Lexus RX400h features a 3.3-liter V6 gasoline engine (model 3MZ-FE) that is part of a hybrid system. This engine works with two electric motors to drive the wheels and the rear axle, providing all-wheel-drive capability. The system uses regenerative braking to recharge the battery and can run on electric power alone at lower speeds.
This video shows a teardown of the Lexus RX400h engine: 57sspeedkar99YouTube · Oct 6, 2025
- Engine type: 3.3-liter, 3MZ-FE V6 gasoline engine.
- Hybrid system: Integrated with two electric motors for a hybrid Synergy Drive.
- Drivetrain: Features an electric four-wheel-drive system (E-Four) on all-wheel-drive models, with a second motor driving the rear axle.
- Operation: The system automatically switches between gasoline and electric power, or a combination of both, to maximize efficiency.
- Regenerative braking: The electric motors act as generators during braking to capture and store energy in the high-voltage battery.
You can watch this video to learn more about the Lexus RX400h driving experience: 59sJJ on CarsYouTube · Sep 13, 2025
How long does the hybrid battery last in a Lexus 400h?
With normal use and maintenance, its battery typically lasts over 10 years or over 200,000 miles!
What is the best year of the Lexus RX?
The best Lexus RX years are generally considered to be the 2013-2015 models for budget-friendly reliability and the 2020-2022 models for a combination of modern features and dependability. Other highly-regarded years include the 2018-2021 range, with 2018 specifically noted for a lack of complaints, and the 2011 model for its strong reliability and comfort.
This video provides a buyer's guide for the 2015-2022 Lexus RX, highlighting models to avoid and features to consider: 51sThe Miles DrivenYouTube · Dec 18, 2024
Recommended years
- 2013-2015: Often recommended for a balance of modern features and proven reliability, with owners praising their durability and smooth ride.
- 2018-2021: This range is highly regarded, especially the 2020-2022 models, which are praised for their dependability and updated infotainment with Apple CarPlay and Android Auto. The 2018 model, in particular, is noted for having no major complaints.
- 2011: Considered a standout year from an earlier generation, this model is praised for its reliability, comfortable and luxurious interior, and user-friendly technology.
Other considerations
- 4th Generation (2016-2022): This generation saw a major redesign, with the 2016-2022 models offering more power and modern technology.
- 5th Generation (2023+): While the newest models are reliable, they also represent a significant change from previous years and may be more expensive.
You can watch this video to learn about the best Lexus RX model to buy from each generation: 43sThe Miles DrivenYouTube · Dec 22, 2024
Factors to consider when buying
- Budget: The 2013-2015 models are a great option if you're on a tighter budget.
- Technology: If you prioritize modern tech like Apple CarPlay and Android Auto, the 2020-2022 models are a better fit.
- Safety: The 2016-2022 models include modern safety features like blind spot monitoring, which may not be available on older models.
- Hybrid vs. Gas: Hybrid models are smoother and offer better fuel economy, but gas models are more affordable upfront.
What is the most common problem with the Lexus RX 400h?
Top 10 Common Problems in Lexus RX 400h and How to Fix Them
- Brake Actuator Malfunction.
- Cooling System Issues.
- Transmission (CVT) Problems.
- Faulty Oxygen Sensors.
- 12V Auxiliary Battery Problems.
- Dashboard Melting (Cosmetic Issue)
- Water Leaks in Rear Hatch or Sunroof.
- Suspension Wear and Noises.
