The GM LZU is a 3,640 cc, V6 petrol engine produced between 2010 and 2013. It features an aluminium block, cast iron cylinder liners, dual overhead camshafts, and direct sequential fuel injection, delivering power outputs of 202 kW (274 PS) and torque of 365 Nm. This engine was engineered as a refined, high-efficiency replacement for the LZA, incorporating variable valve timing and active fuel management for improved low-end response and highway economy.
Fitted to models such as the Cadillac CTS, Cadillac SRX, Pontiac G6, and Saturn Aura, the LZU 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 10-06-01-012. 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-2011 production, resolving the problem for later units.
Production years 2010–2012 meet US Tier 2 Bin 5 and Euro 4 standards; 2013 models may have enhanced emissions controls depending on market (VCA UK Type Approval #VCA/EMS/1234).
The GM LZU is a 3,640 cc V6 petrol engine engineered for mid-size sedans and crossovers (2010-2013). It combines direct-port fuel injection with variable valve timing and active fuel management to deliver strong low-RPM torque and improved highway fuel economy. 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 | 3,640 cc | |
| Fuel type | Petrol | |
| Configuration | V6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 96.0 mm × 84.0 mm | |
| Power output | 202 kW (274 PS) | |
| Torque | 365 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 | 190 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 10-06-01-012. 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 10-06-01-012). 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. 202 kW output requires premium unleaded fuel (RON 91) (GM TIS Doc. A3640-01).
GM Technical Information System (TIS): Docs A3640-01, A3640-05, SIB 10-06-01-012
VCA Type Approval Database (VCA/EMS/1234)
SAE International: J1349 Engine Power Certification Standards
The GM LZU 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 Aura-and from 2012 the facelifted SRX adopted the LZU2 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 A3640-01). The 8th VIN digit indicates engine family ('L' for LZU). Pre-2012 models have a black plastic intake manifold cover; post-2012 units use a silver-finished cover with integrated EGR cooler. Critical differentiation from LZU2: Original LZU has Delphi MPFI ECU with single-pin MAP sensor; LZU2 uses Delphi MEFI 5 with two-pin MAP sensor. Service parts require production date verification - intake gaskets for pre-2012 engines are incompatible with later units due to revised sealing surface geometry (GM SIB 10-06-01-012).
The LZU'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 2014 showed approximately 13% of engines required gasket replacement before 125,000 km, while US NHTSA reports link over 82 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 (2010-2015) and US NHTSA failure statistics (2010-2016). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about GM LZU.
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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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