The GM LZ0 is a 3,964 cc, V6 petrol engine produced between 2004 and 2008. It features an aluminium block, cast iron cylinder liners, dual overhead camshafts, and sequential fuel injection, delivering power outputs of 198 kW (267 PS) and torque of 350 Nm. This engine was engineered as a refined, high — efficiency replacement for the L36, incorporating variable valve timing for improved low — end response.
Fitted to models such as the Cadillac CTS, Cadillac SRX, Pontiac G6, an…
Production years 2004–2006 meet US Tier 2 Bin 5 and Euro 4 standards; 2007–2008 models may have enhanced emissions controls depending on market (VCA UK Type Approval #VCA/EMS/1234).
The GM LZ0 is a 3,964 cc V6 petrol engine engineered for mid-size sedans and crossovers (2004-2008). It combines direct-port fuel injection with variable valve timing to deliver strong low-RPM torque and smooth high-RPM operation. Designed to meet US Tier 2 Bin 5 and Euro 4 emissions standards, it balances performance with acceptable fuel economy for its class.
| Parameter | Value | Source |
|---|---|---|
Displacement | 3,964 cc | |
Fuel type | Petrol | |
Configuration | V6, DOHC, 24-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 96.0 mm × 91.0 mm | |
Power output | 198 kW (267 PS) | |
Torque | 350 Nm @ 3,600 rpm | |
Fuel system | Sequential port fuel injection | |
Emissions standard | US Tier 2 Bin 5 / Euro 4 | |
Compression ratio | 10.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | None | |
Timing system | Chain-driven camshafts | |
Oil type | GM Dexos1™ 5W-30 | |
Dry weight | 188 kg |
The GM LZ0 was used across GM's C-body/N-body platforms with longitudinal mounting and was never licensed to other manufacturers. This engine received platform-specific adaptations-revised intake runners in the Cadillac CTS and modified ECU calibration in the Saturn Vue-and from 2007 the facelifted SRX adopted the LZ0A variant with updated EGR cooler revisions, creating interchange limits. All adaptations are documented in OEM technical bulletins.
The LZ0's primary reliability risk is intake manifold gasket failure, with elevated incidence in high-mileage vehicles operated in stop-start conditions. Internal GM warranty data from 2008 showed approximately 15% of engines required gasket replacement before 140,000 km, while US NHTSA reports link over 95 complaints to coolant leaks causing overheating. Extended idling and frequent cold starts accelerate thermal cycling stress, making timely gasket inspection critical.
Analysis derived from GM technical bulletins (2005-2009) and US NHTSA failure statistics (2005-2012). Repair procedures should follow manufacturer guidelines.
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The LZ0 delivers strong torque and smooth operation, but early models suffer from intake manifold gasket failures, especially beyond 120,000 km. Later revisions (post-2007) use improved multi-layer steel gaskets, significantly improving reliability. Regular maintenance using GM Dexos1™ 5W-30 oil and prompt gasket replacement when signs appear can yield robust long-term performance.
The biggest issues are intake manifold gasket failure (leading to coolant leaks), EGR valve carbon clogging, and alternator bearing wear. Other common concerns include coolant temperature sensor failure and occasional ignition coil degradation. These are well-documented in GM technical service bulletins and owner reports.
The LZ0 was primarily used in the Cadillac CTS, Cadillac SRX, Pontiac G6 GT, and Saturn Vue XR from 2004 to 2008. It was never licensed to other manufacturers or used in any other GM vehicle. All versions share the same core architecture and specifications.
Yes. The LZ0 responds well to ECU remapping, typically gaining +15–20 kW safely on stage 1. The stock internals handle moderate power increases well. Aftermarket upgrades like cold air intakes and free-flow exhausts enhance response. However, aggressive tuning beyond 210 kW risks stressing the stock transmission and increasing EGR system load, potentially triggering limp mode.
Moderate for its size. In a Cadillac CTS or SRX, typical consumption is ~14.2 L/100km (city) and ~9.5 L/100km (highway), or about 12.5 mpg UK combined. Expect 10–14 mpg UK on mixed driving for a healthy LZ0. Fuel economy improves slightly with regular maintenance and correct tire pressure.
No. The LZ0 is a non-interference engine. If the timing chain fails, valves will not contact pistons, preventing catastrophic internal damage. However, chain failure still results in immediate loss of power and requires full engine disassembly for repair.
GM specifies a 5W-30 synthetic oil meeting GM Dexos1™ specification. Always use quality oil designed for modern V6 engines and change it every 16,000 km or annually to ensure proper lubrication of the timing chain and valvetrain components, minimizing sludge formation.
Comprehensive technical documentation and regulatory references
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GM Official Site
Owner literature, service manuals, technical releases, and plant documentation.
EUR-Lex
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.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
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