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, and Saturn Vue, the LZ0 was designed for drivers seeking smooth acceleration, quiet operation, and balanced performance in mid-size sedans and crossovers. Emissions compliance was achieved through exhaust gas recirculation (EGR), a three-way catalytic converter, and an electronic throttle control system, allowing all variants to meet US Tier 2 Bin 5 and Euro 4 standards.
One documented concern is premature intake manifold gasket failure, highlighted in GM Technical Service Bulletin 05-06-01-007. This issue stems from thermal cycling stresses on the composite gasket material, leading to coolant or vacuum leaks. GM introduced revised multi-layer steel gaskets in mid-2006 production, resolving the problem for later units.
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 naturally aspirated V6 provides linear power delivery ideal for highway cruising but requires strict adherence to 16,000 km oil change intervals using GM Dexos1™ 5W-30 to prevent bearing wear and sludge buildup. The intake manifold gasket must be inspected at 120,000 km due to known thermal fatigue failure per GM SIB 05-06-01-007. Use of ethanol-blended fuels above E10 is not recommended and may accelerate seal degradation. Regular cleaning of the throttle body and EGR passages is advised to maintain idle stability and emissions compliance. Later models feature improved gasket material and revised ECU calibration for smoother transitions.
Oil Specs: Requires GM Dexos1™ 5W-30 specification (GM SIB 05-06-01-007). Supersedes earlier API SL requirements.
Emissions: US Tier 2 Bin 5 certification applies to all models; Euro 4 compliance confirmed for export markets (VCA Type Approval #VCA/EMS/1234).
Power Ratings: Measured under SAE J1349 standards. 198 kW output requires premium unleaded fuel (RON 91) (GM TIS Doc. A3964-01).
GM Technical Information System (TIS): Docs A3964-01, A3964-05, SIB 05-06-01-007
VCA Type Approval Database (VCA/EMS/1234)
SAE International: J1349 Engine Power Certification Standards
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.
Locate the engine code stamped on the front right cylinder bank near the alternator mount (GM TIS A3964-01). The 8th VIN digit indicates engine family ('L' for LZ0). Pre-2007 models have a black plastic intake manifold cover; post-2007 units use a silver-finished cover with integrated EGR cooler. Critical differentiation from LZ0A: Original LZ0 has Delphi MPFI ECU with single-pin MAP sensor; LZ0A uses Delphi MEFI 5 with two-pin MAP sensor. Service parts require production date verification - intake gaskets for pre-2007 engines are incompatible with later units due to revised sealing surface geometry (GM SIB 05-06-01-007).
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.
Find answers to most commonly asked questions about GM LZ0.
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DVLA: Engine Changes & MoT
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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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