The Chevrolet LW9 is a 3,527 cc, naturally aspirated V6 gasoline engine produced between 2004 and 2011. It features dual overhead camshafts (DOHC), variable valve timing (VVT), and sequential fuel injection, delivering smooth power delivery and strong mid-range torque. In standard tuning it produces 181 kW (246 PS) with 320 Nm of torque, primarily used in mid-size and full-size front-wheel-drive applications.
Fitted to models such as the Chevrolet Impala (8th gen), Monte Carlo, and Pontiac Grand Prix, the LW9 was engineered for refined highway cruising and dependable performance. Emissions compliance was achieved through a three-way catalytic converter and closed-loop fuel control, meeting U.S. Tier 2 Bin 5 standards depending on regional calibration.
One documented concern is intake manifold gasket failure due to thermal cycling and material degradation, noted in General Motors Service Bulletin #05-06-01-007. This issue stems from the composite two-piece intake design, which can develop leaks under sustained temperature variation. From 2007 onward, revised gasket materials and updated torque specifications were implemented across production lines.
Chevrolet
Production years 2004–2006 meet U.S. Tier 2 Bin 5; 2007–2011 models comply with LEV II standards (EPA Certification #EPA/ENG/7894).
The Chevrolet LW9 is a 3,527 cc V6 gasoline engine engineered for large front-wheel-drive platforms (2004–2011). It combines DOHC architecture with continuously variable valve timing to deliver smooth power delivery and reduced emissions. Designed to meet U.S. emissions standards, it balances refinement with performance for premium applications.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,527 cc | |
| Fuel type | Gasoline (RON 87 min) | |
| Configuration | V6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 99.0 mm × 76.0 mm | |
| Power output | 181 kW (246 PS) @ 5,600 rpm | |
| Torque | 320 Nm @ 4,400 rpm | |
| Fuel system | Sequential multi-port fuel injection | |
| Emissions standard | U.S. Tier 2 Bin 5 / LEV II | |
| Compression ratio | 10.1:1 | |
| Cooling system | Closed-loop liquid cooling | |
| Turbocharger | Not applicable | |
| Timing system | Dual-row roller chain (interference design) | |
| Oil type | GM Standard Oil 5W-30 | |
| Dry weight | 184 kg |
The naturally aspirated DOHC design provides linear throttle response but requires adherence to 10,000 km oil change intervals to prevent intake gasket degradation and lifter wear. GM Standard Oil 5W-30 is recommended due to its additive package supporting hydraulic lifters and camshaft lubrication. Extended operation in stop-start conditions or high ambient temperatures increases stress on the composite intake manifold. The engine's tolerance for lower-octane fuel (RON 87) makes it suitable for broad market use, though sustained detonation can accelerate gasket failure. Post-2007 models feature revised intake gasket materials; pre-2007 units should be inspected per GM SIB 05-06-01-007. Catalytic converter longevity depends on maintaining proper air-fuel ratio and avoiding prolonged rich conditions.
Oil Specs: Requires GM Standard Oil 5W-30 specification (GM SIB 05-06-01-007). Substitution with ILSAC GF-4 acceptable if meeting GM6094M.
Emissions: U.S. Tier 2 Bin 5 applies to North American models (2004–2006); LEV II certification applies to later variants (2007–2011) (EPA Certification #EPA/ENG/7894).
Power Ratings: Measured under SAE J1349 standards. Full output requires fuel with RON 87 or higher (GM TIS Doc. 410-ENG-13).
General Motors Technical Information System (TIS): Docs 410-TEC-07, 410-FUE-10, SIB 05-06-01-007
EPA Engine Certification Database (EPA/ENG/7894)
SAE International: J1349 Engine Power Certification Standards
The Chevrolet LW9 was used across Chevrolet's W-body platform with transverse mounting and shared with Pontiac and Oldsmobile in North American markets. This engine received platform-specific adaptations-reinforced mounts in the Impala LTZ and tuned exhaust manifolds in the Monte Carlo SS-and from 2007 the facelifted Grand Prix adopted revised intake gaskets and updated PCM calibration, creating interchange limits. Partnerships allowed Pontiac's Grand Prix GXP to use the LW9 with performance tuning. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the front passenger-side cylinder block near the cylinder head (GM TIS 410-ID-08). The 8th VIN digit indicates engine type ('H' for LW9 series). Pre-2007 models have silver valve covers with ribbed finish; post-2007 units use dark blue valve covers. Critical differentiation from L36: LW9 has variable valve timing and uses a composite intake manifold, while L36 lacks VVT and uses cast aluminum intake. Service parts require production date verification - intake gaskets for engines before 06/2007 are incompatible with later units due to material redesign (GM SIB 05-06-01-007).
The LW9's primary reliability risk is intake manifold gasket failure on early builds, with elevated incidence in high-temperature climates. Internal GM quality reports from 2006 indicated a significant share of pre-2007 engines requiring intake replacement before 150,000 km, while U.S. NHTSA records show increased engine-related service events in fleet-trim Impala models. Sustained thermal cycling and delayed maintenance increase crack formation, making coolant quality and interval adherence critical.
Analysis derived from General Motors technical bulletins (2004-2011) and U.S. National Highway Traffic Safety Administration failure statistics (2005-2013). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CHEVROLET LW9.
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