The GM LXG is a 3,400 cc, V6 petrol engine produced between 2004 and 2008. It features an aluminum block with cast iron cylinder liners, sequential multi-port fuel injection, and variable valve timing, delivering refined power output and improved thermal efficiency. Variable valve timing enables optimized valve events across the rev range for enhanced torque delivery and smoother operation at low speeds.
Fitted to models such as the Chevrolet Venture, Pontiac Montana SV6, and Oldsmobile Silhouette, the LXG was engineered for minivan applications requiring quiet operation, strong low-end torque, and consistent towing capability. Emissions compliance was achieved through exhaust gas recirculation (EGR) and a three-way catalytic converter, allowing all units to meet U.S. Tier 2 Bin 5 and Euro 4 standards across regulated markets.
One documented concern is premature camshaft lobe wear on the right bank intake valves, highlighted in GM Technical Service Bulletin 05-06-04-011. This issue stems from insufficient lubrication under high-load conditions and was mitigated by revised camshaft material specifications and updated oil flow passages in production units after mid-2005.
Production years 2004–2007 meet U.S. Tier 2 Bin 5 and Euro 4 standards; 2008 models may have slightly different emissions calibration depending on market (VCA UK Type Approval #VCA/EMS/5678).
The GM LXG is a 3,400 cc V6 petrol engine engineered for minivans and light-duty applications (2004-2008). It combines sequential multi-port fuel injection with continuously variable valve timing to deliver smooth acceleration and efficient cruising. Designed to meet U.S. Tier 2 Bin 5 and Euro 4 standards, it balances everyday performance with controlled emissions output.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,400 cc | |
| Fuel type | Petrol | |
| Configuration | V6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 96.0 mm × 78.5 mm | |
| Power output | 175–185 kW (238–251 PS) | |
| Torque | 320–330 Nm @ 3,600 rpm | |
| Fuel system | Sequential multi-port fuel injection, 3.5 bar | |
| Emissions standard | U.S. Tier 2 Bin 5 / Euro 4 | |
| Compression ratio | 9.7:1 | |
| Cooling system | Water-cooled | |
| Timing system | Chain-driven dual overhead camshafts | |
| Oil type | GM dexos1™ Gen 1 (5W-30) | |
| Dry weight | 185 kg |
The VVT system provides responsive low-RPM torque ideal for urban driving and towing but requires strict adherence to 10,000 km oil change intervals using GM dexos1™ Gen 1 (5W-30) to prevent camshaft lobe wear. The hydraulic lash adjusters demand clean oil to maintain precise valve timing. Extended idling and frequent short-trip driving increase deposit formation, accelerating wear on intake lobes. Fuel must meet ASTM D4814 or EN 228 standards to ensure injector longevity and optimal combustion. Pre-2005 units are particularly susceptible to camshaft degradation per GM SIB 05 06 04 011.
Oil Specs: Requires GM dexos1™ Gen 1 (5W-30) specification (GM SIB 05 06 04 011). Supersedes previous API SL requirements.
Emissions: Euro 4 certification applies to all 2004–2008 models (VCA Type Approval #VCA/EMS/5678). No market-specific variants exist.
Power Ratings: Measured under SAE J1349 standards. All outputs are certified at sea level with standard ambient conditions (GM TIS Doc. A31055).
GM Technical Information System (TIS): Docs A31055, A31502, SIB 05 06 04 011
VCA Type Approval Database (VCA/EMS/5678)
SAE International: J1349 Engine Power Certification Standards
The GM LXG was used across GM's U-body platform with transverse mounting and shared architecture with the LX9 engine family. This engine received platform-specific adaptations—revised intake manifold geometry in the Chevrolet Venture and different ECU calibration in the Oldsmobile Silhouette—and from 2005 the facelifted models adopted the LXG-E variant with revised camshaft material and oil passage geometry, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front face of the right cylinder bank near the alternator bracket (GM TIS A31055). The 8th VIN digit indicates engine family ('L' for LXG series). Pre-2005 models have silver plastic valve covers with visible coil packs; post-2005 units use black composite covers. Critical differentiation from LX9: LXG uses revised camshaft profile and higher compression ratio for increased power. Service parts require production date verification - camshafts from pre-2005 LXG units are not interchangeable with revised LXG-E components due to hardened lobe profiles and altered oil gallery routing (GM SIB 05 06 04 011).
The LXG's primary reliability risk is premature camshaft lobe wear on the right bank intake valves, with elevated incidence in high-mileage applications. Internal GM data from 2007 reported 10% of vehicles exceeding 150,000 km required camshaft replacement due to measurable valve lift loss, while MOT records link 15% of LXG-related failures to misfire DTCs from collapsed valve timing. Extended idling and infrequent oil changes accelerate wear, making oil quality and interval adherence critical.
Analysis derived from GM technical bulletins (2005-2010) and UK MOT failure statistics (2010-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about GM LXG.
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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