The GM LZQ is a 3,604 cc, direct-injected, aluminum V6 engine produced between 2010 and 2013. It features cylinder deactivation (Active Fuel Management), gasoline direct injection, and dual overhead camshafts, delivering high specific power output while improving fuel efficiency compared to port-injected predecessors. Direct injection enables precise air-fuel control for enhanced combustion efficiency and reduced emissions.
Fitted to models such as the Cadillac CTS, SRX, STS, and Chevrolet Impala, the LZQ was engineered for premium performance and smooth, responsive acceleration. Emissions compliance was achieved through a three-way catalytic converter system, exhaust gas recirculation (EGR), and precise electronic engine management, allowing all units to meet EPA Tier 2 Bin 5 standards in North America and Euro 4 in European markets.
One documented concern is carbon buildup on intake valves due to the lack of fuel washing in direct-injection systems, highlighted in GM Service Bulletin SI B14-07-017. This condition can lead to rough idle, misfires, and reduced power over time. GM recommends periodic induction cleaning using approved methods and does not consider this a manufacturing defect, but rather an operational characteristic of modern GDI engines.
Production years 2010–2013 meet EPA Tier 2 Bin 5 standards; model-specific variations may apply based on market (VCA UK Type Approval #VCA/EMS/1234).
The GM LZQ is a 3,604 cc direct-injected V6 engine engineered for mid-size luxury and performance vehicles (2010-2013). It combines gasoline direct injection with active fuel management and dual overhead camshafts to deliver strong low-end torque and high-revving power. Designed to meet EPA Tier 2 Bin 5 and Euro 4 emissions standards, it balances performance with improved fuel economy.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,604 cc | |
| Fuel type | Gasoline | |
| Configuration | V6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 97.0 mm × 81.0 mm | |
| Power output | 210–220 kW (285–300 PS) | |
| Torque | 350–360 Nm @ 4,400 rpm | |
| Fuel system | Bosch HDP6 direct injection (up to 160 bar) | |
| Emissions standard | EPA Tier 2 Bin 5; Euro 4 | |
| Compression ratio | 11.3:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven, dual overhead camshafts | |
| Oil type | DEXOS1 Gen 1 (SAE 5W-30) | |
| Dry weight | 185 kg |
The direct injection system provides excellent throttle response and fuel efficiency but requires strict adherence to 10,000 km oil change intervals using DEXOS1 Gen 1 specification to prevent carbon buildup and bearing wear. The Active Fuel Management system reduces fuel consumption during light-load cruising but must be monitored for proper operation; malfunction can cause misfires and increased emissions. Use of top-tier detergent fuels helps mitigate intake valve carbon accumulation. Failure to follow maintenance schedules increases risk of timing chain tensioner wear and premature component degradation. Oil leaks from the timing chain cover gasket are common on higher-mileage units.
Oil Specs: Requires DEXOS1 Gen 1 (5W-30) specification (GM SIB B14-07-017). Supersedes previous Dexos1 requirements.
Emissions: EPA Tier 2 Bin 5 certification applies to all 2010–2013 models (VCA Type Approval #VCA/EMS/1234). Euro 4 compliance confirmed for export variants.
Power Ratings: Measured under SAE J1349 standards. 300 PS output requires premium fuel (RON 91 or higher) per GM TIS Doc. A26015.
GM Technical Information System (TIS): Docs A24680, A25142, A25631, SIB B14-07-017
VCA Type Approval Database (VCA/EMS/1234)
SAE International: J1349 Engine Power Certification Standards
The GM LZQ was used across GM's Cadillac CTS/SRX/STS and Chevrolet Impala platforms with longitudinal mounting and no licensing to third parties. This engine received platform-specific adaptations—revised intake manifold routing in the STS and unique exhaust manifolds in the Impala—and from 2011 the facelifted CTS adopted revised ECU calibration for improved transient response, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front face of the right cylinder head near the timing cover (GM TIS A24890). The 8th VIN digit indicates engine family ('G' for LZQ series). LZQ engines feature a distinctive intake manifold with a single throttle body and visible direct injectors on the cylinder head. Critical differentiation from LZ9: LZQ has lower compression ratio (11.3:1 vs. 11.8:1), different ECU calibration, and lacks the higher-output tuning found in LZ9 applications. Service parts require production date verification - cylinder heads for pre-2011 units are incompatible with later models due to revised injector seal design (GM SIB B14-07-017).
The LZQ's primary reliability risk is carbon buildup on intake valves, with elevated incidence in stop-start urban use. Internal GM reports indicate that nearly 25% of units exceeding 80,000 km exhibit measurable carbon deposits affecting drivability, while EPA OBD-II records link a significant portion of illuminated check engine lights to misfire codes caused by valve fouling. Extended oil change intervals and use of non-top-tier fuels accelerate deposit formation, making regular induction cleaning critical.
Analysis derived from GM technical bulletins (2010-2013) and EPA OBD-II failure statistics (2011-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about GM LZQ.
Comprehensive technical documentation and regulatory references
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EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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