Under the hood of the 2009 Lexus RX 350 sits the 3.5-liter 2GR-FE V6 engine, a bulletproof powerplant known for smooth delivery and long-term durability. If you're tracing vacuum lines, tracking down an oil leak, or replacing a serpentine belt, looking at a flat factory schematic isn't always enough. You need to know where major components sit, how they interact, and what common trouble spots to watch for on this specific model year.
This guide breaks down the core architecture of the 2009 Lexus RX 350 engine bay. We will map out the accessory drive, vacuum routing, cooling layout, and timing components to give you a practical mental map of how everything fits together.
Core Engine Specifications and Layout
The 2GR-FE is a 60-degree V6 featuring an aluminum block and aluminum cylinder heads. It utilizes dual overhead cams (DOHC) per bank with four valves per cylinder, controlled by Toyota's Dual VVT-i (Variable Valve Timing with intelligence) system.
- Displacement: 3,456 cc (210.9 cubic inches)
- Bore and Stroke: 94.0 mm × 83.0 mm (3.70 in × 3.27 in)
- Compression Ratio: 10.8:1
- Horsepower: 270 hp at 6,200 rpm
- Torque: 248 lb-ft at 4,700 rpm
- Firing Order: 1-2-3-4-5-6 (Bank 1 is the rear bank closer to the firewall; Bank 2 is the front bank facing the radiator)
Unlike older timing-belt setups, this engine uses a timing chain layout. Knowing bank orientations saves plenty of guesswork when dealing with ignition coils, fuel injectors, or oxygen sensors.
Serpentine Belt and Accessory Routing
When you stand facing the engine bay, the serpentine belt system sits on the passenger-side (right side) of the motor. It routes power from the crankshaft pulley to several key accessories.
- The Automatic Belt Tensioner: Located near the middle-lower section of the accessory drive. It maintains constant tension via an internal spring. A failing tensioner will cause a rhythmic squeak or chirping noise at idle.
- Alternator: Positioned high on the upper passenger side, making it relatively straightforward to swap out if the charging system fails.
- Power Steering Pump / Air Conditioning Compressor: The A/C compressor sits low on the passenger side, while the power steering setup relies on an electronic power steering assist module or a traditional hydraulic pump depending on sub-trims, though 2009 RX 350 models use a reliable hydraulic rack driven by a remote fluid reservoir.
- Idler Pulleys: There are typically two smooth or grooved idler pulleys that guide the belt. Seized bearings in these pulleys are a frequent source of high-pitched whining noises under acceleration.
To replace the serpentine belt, you'll need a 19mm box-end wrench to rotate the tensioner clockwise, relieving pressure off the belt while you slip it off the alternator pulley last.
Intake Manifold and Vacuum System Layout
The top of the engine is dominated by a large cast aluminum and composite intake plenum. This feeds air into the cylinders through the Acoustic Control Induction System (ACIS), which alters intake runner length dynamically to optimize low-end torque and high-end horsepower.
- Electronic Throttle Body: Mounted facing the driver's side (left side) of the intake plenum. It relies on a drive-by-wire system (ETCS-i), meaning there is no physical throttle cable attached to the gas pedal. Carbon buildup around the butterfly valve here often triggers rough idling or stalling.
- PCV Valve Location: Positioned on the valve cover of Bank 1 (rear bank). It routes crankcase vapors back into the intake stream. When the rubber grommet hardens over time, it leaks oil down the back of the engine block.
- EVAP Purge VSV (Vacuum Switching Valve): Mounted near the intake plenum on the passenger side. A clicking noise or an evaporative emissions check-engine code usually points directly to this component or its associated vacuum hoses.
Cooling System Component Map
Managing thermal load on a transversely mounted V6 requires a tight network of hoses and plastic-tanked radiators.
- Water Pump: Located on the passenger side, driven internally behind the timing chain cover. A failing water pump on a 2GR-FE often manifests as pink crusty coolant residue weeping from the weep hole or a low coolant warning on the dash.
- Thermostat Housing: Situated on the lower driver's side of the engine block where the lower radiator hose meets. It's a conventional wax-pellet thermostat that fails open (causing poor cabin heater performance) or closed (causing overheating).
- Radiator and Dual Electric Fans: Sitting right behind the front bumper fascia, controlled by the Engine Control Module (ECM) based on coolant temperature sensor readings.
Always use Toyota Super Long Life Coolant (pink) when servicing this system to prevent galvanic corrosion in the aluminum radiator cores.
Ignition and Fuel Delivery Diagram
Ignition on the 2009 RX 350 is handled by a Direct Ignition System (DIS) featuring individual coil-on-plug units for each of the six cylinders.
- Front Bank (Bank 2): Cylinders 2, 4, and 6 face forward and are completely unobstructed. You can swap spark plugs or ignition coils on this bank in under twenty minutes with basic hand tools.
- Rear Bank (Bank 1): Cylinders 1, 3, and 5 sit against the firewall underneath the upper intake plenum. Accessing these spark plugs requires unbolting and lifting the upper intake manifold plenum, requiring a fresh intake gasket set during the job.
- Fuel Rail and Injectors: Port fuel injectors sit directly beneath the intake runners, spraying fuel into each intake port. O-ring leaks here will smell strongly of raw gasoline after cold starts.
Frequently Asked Questions
Where is the oil filter located on a 2009 Lexus RX 350?
The oil filter uses a replaceable paper element housed inside a metal canister cap rather than a traditional spin-on metal filter. It sits near the bottom front of the engine block on the passenger side, easily accessible if you jack up the front end or use a service ramp.
Does the 2009 Lexus RX 350 have a timing belt or timing chain?
It uses a steel timing chain designed to last the lifetime of the engine, provided you keep up with regular 5,000-mile synthetic oil changes. There is no scheduled replacement interval like an old rubber timing belt.
What causes oil leaks at the rear of the 2GFR-FE engine?
The most common culprit is the rubber section of the VVTi oil supply line on early models, or degradation of the valve cover gasket on Bank 1. Lexus issued a recall years ago for early rubber oil lines, replacing them with all-metal updated lines. Check yours immediately to prevent catastrophic oil loss.
How do I clear a rough idle on this vehicle?
A rough idle is usually caused by heavy carbon fouling on the throttle body butterfly valve or a dirty Mass Air Flow (MAF) sensor located right after the air filter box. Clean both using dedicated electronic cleaner sprays before replacing expensive sensors.
