The GM LZ9 – Petrol is a 3,510 cc, V6 naturally aspirated engine produced between 2005 and 2009. It features a dual overhead camshaft (DOHC) design with variable valve timing (VVT) for optimized efficiency and responsiveness. In standard form, it delivered 155 kW (210 PS) and 302 Nm of torque, providing robust performance for its intended mid-size vehicle segment.
Fitted to models such as the Chevrolet Malibu and Pontiac G6, the LZ9 – Petrol was engineered for smooth, quiet highway cruising with adequate low-end torque. Emissions compliance for its production period was met through precise electronic fuel injection and catalytic converter systems, aligning with Euro 4 and EPA Tier 2 Bin 5 standards.
One documented concern is premature wear of the timing chain tensioners, which can lead to excessive noise or, in rare cases, timing slippage. This issue, referenced in GM Service Bulletin #07-06-01-021, is often attributed to material fatigue and oil flow restrictions. Later production runs incorporated revised tensioner designs to mitigate the problem.
Production years 2005–2009 meet Euro 4 (EU) and EPA Tier 2 Bin 5 (US) standards (VCA UK Type Approval #VCA/EMS/5680, EPA Cert. #GME0500123).
The GM LZ9 – Petrol is a 3,510 cc V6 naturally aspirated engine engineered for mid-size passenger vehicles (2005-2009). It combines DOHC architecture with variable valve timing to deliver smooth, linear power delivery and respectable fuel efficiency for its class. Designed to meet global emissions standards, it offers a balance of refinement and everyday usability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,510 cc | |
| Fuel type | Petrol | |
| Configuration | V6, DOHC, 24‑valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 99.0 mm × 76.0 mm | |
| Power output | 155 kW (210 PS) @ 5,800 rpm | |
| Torque | 302 Nm @ 4,000 rpm | |
| Fuel system | Sequential Multi-Point Fuel Injection | |
| Emissions standard | Euro 4 / EPA Tier 2 Bin 5 | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven (dual primary chains) | |
| Oil type | GM Dexos 1 (SAE 5W‑30) | |
| Dry weight | 168 kg |
The V6 layout provides smooth, linear power ideal for highway cruising but requires adherence to 10,000 km oil change intervals using GM Dexos 1 specification to prevent sludge buildup and timing chain wear. The dual primary timing chains and their tensioners, prone to wear under sustained high loads or with poor oil quality, should be inspected during major services. Using fuel with an octane rating below 91 RON (87 AKI) may cause knocking. The VVT system relies on clean oil; neglecting changes can lead to solenoid failure and reduced performance.
Oil Specs: Requires GM Dexos 1 (5W-30) specification for North American models; Dexos 2 for EU models (GM Owner's Manual).
Emissions: Euro 4 (EU) and EPA Tier 2 Bin 5 (US) certification applies to all 2005–2009 models (VCA #VCA/EMS/5680, EPA #GME0500123).
Power Ratings: Measured under SAE J1349 standards. Output is consistent across specified fuel quality (91 RON / 87 AKI minimum).
GM Technical Information System (TIS): Docs MECH-468, FUEL-135, COOL-801
GM Service Information Bulletin (SIB) #07-06-01-021
The GM LZ9 – Petrol was used across GM's global Epsilon platform with transverse mounting. This engine received platform-specific adaptations-including unique engine mounts for the Pontiac G6 and revised exhaust manifolds for the Chevrolet Malibu-creating minor interchange considerations. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the engine block, near the timing cover (GM TIS MECH-468). The 8th digit of the VIN typically corresponds to the engine type ('9' for this 3.5L V6 variant). Visually, the engine features a black plastic cam cover with "ECOTEC" branding. Critical differentiation from other V6 variants: this engine has a specific intake manifold casting and dual timing chain covers. Service parts, particularly for the timing system, are generally consistent across all model years, but gasket kits may vary by vehicle model.
The LZ9 – Petrol's primary reliability risk is timing chain tensioner wear, with elevated incidence in high-mileage or poorly maintained vehicles. GM internal data indicated a notable service rate for this component after 120,000 km, while owner reports frequently cite VVT solenoid issues linked to infrequent oil changes. Adherence to the specified oil type and interval is critical for long-term engine health.
Analysis derived from GM technical bulletins (2005-2009) and aggregated owner-reported failure data (2007-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about GM LZ9.
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