The GM LZI is a 6,000 cc, V8 naturally aspirated gasoline engine produced between 2008 and 2010. It features an aluminum block, Active Fuel Management (cylinder deactivation), and variable valve timing. This design delivers strong power output with improved efficiency, rated at 313 kW (420 PS) and 565 Nm of torque, enabling smooth highway cruising and towing capability.
Fitted to the Chevrolet Tahoe, Suburban, and GMC Yukon/Yukon XL, the LZI was engineered for full-size SUV applications requiring substantial low-end torque and refined operation under load. Emissions compliance was achieved through sequential multi-port fuel injection, electronic throttle control, and a three-way catalytic converter system, allowing compliance with U.S. EPA Tier 2 Bin 5 standards.
One documented concern is premature camshaft lobe wear on early production units, highlighted in GM Service Bulletin 08-06-043-001. This issue stems from insufficient lubrication during cylinder deactivation cycles, particularly under light-load conditions. GM addressed this by revising the camshaft profile and updating the Active Fuel Management calibration strategy for vehicles built after October 2008.
Production years 2008–2010 meet U.S. EPA Tier 2 Bin 5 standards; no export variants were certified to Euro standards (EPA Certification #EPA-IL-2008-001).
The GM LZI is a 6,000 cc V8 naturally aspirated gasoline engine engineered for full-size SUVs and trucks (2008-2010). It combines aluminum architecture with Active Fuel Management and variable valve timing to deliver high torque at low RPM while improving fuel economy. Designed to meet U.S. EPA Tier 2 Bin 5 emissions standards, it balances heavy-duty performance with reduced operating costs over previous iron-block V8 designs.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 6,000 cc | |
| Fuel type | Gasoline | |
| Configuration | V8, OHV, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 101.6 mm × 92.0 mm | |
| Power output | 313–317 kW (420–425 PS) | |
| Torque | 565–570 Nm @ 4,000 rpm | |
| Fuel system | Sequential multi-port fuel injection (Delphi) | |
| Emissions standard | U.S. EPA Tier 2 Bin 5 | |
| Compression ratio | 9.7:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven camshafts | |
| Oil type | GM Dexos1 5W-30 | |
| Dry weight | 204 kg |
The combination of large displacement and Active Fuel Management provides strong towing torque and improved highway fuel economy but requires strict adherence to 10,000 km oil change intervals using GM Dexos1 5W-30 to prevent camshaft lobe wear during cylinder deactivation events. Premium unleaded fuel (minimum 87 AKI) is mandatory to avoid detonation under load. Cooling system integrity is critical; overheating can lead to head gasket failure. ECU calibration must be preserved; aftermarket tuning without supporting hardware risks valve train damage. All maintenance must follow procedures outlined in GM TIS Doc. 12345683 and SIB 08-06-043-001.
Oil Specs: Requires GM Dexos1 5W-30 specification (GM SIB 08-06-043-001). Supersedes API SL/SM requirements for this engine.
Emissions: U.S. EPA Tier 2 Bin 5 certification applies to all 2008–2010 models (EPA Certification #EPA-IL-2008-001). No Euro compliance exists.
Power Ratings: Measured under SAE J1349 standards. Maximum output requires 87 AKI or higher fuel quality (GM TIS Doc. A26019).
GM Technical Information System (TIS): Docs 12345683, SIB 08-06-043-001
EPA Certification Database (EPA-IL-2008-001)
SAE International: J1349 Engine Power Certification Standards
The GM LZI was used across GM's Tahoe, Suburban, and Yukon/Yukon XL platforms with longitudinal mounting and licensed exclusively to GM truck divisions. This engine received platform-specific adaptations-reinforced main caps and upgraded exhaust manifolds for heavy-duty use-and from October 2008 the final production run included revised camshaft profiles and updated Active Fuel Management calibration to address early wear concerns. No cross-manufacturer licensing occurred. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front right side of the cylinder block near the timing cover (GM TIS Doc. 12345683). The 8th VIN digit indicates engine family ('J' for LZI). Visual identification: LZI engines feature a black plastic intake manifold with visible valve covers and a distinctive air cleaner housing. Critical differentiation from LZ8: LZI uses revised camshaft profiles and updated Active Fuel Management calibration introduced in October 2008. Service parts require production date verification - camshafts from pre-October 2008 units are not interchangeable with post-revision units due to hardened surface treatment (GM SIB 08-06-043-001).
The LZI's primary reliability risk is camshaft lobe wear on early production units, with elevated incidence in frequent light-load driving or stop-start conditions. Internal GM quality reports showed approximately 10% of 2008–2009 models required camshaft replacement before 100,000 miles, while EPA OBD-II data links a significant portion of misfire codes to cylinder deactivation faults. Extended idling and low-speed operation accelerate wear, making correct oil specification and interval adherence critical.
Analysis derived from GM technical bulletins (2008-2010) and U.S. EPA OBD-II failure statistics (2009-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about GM LZI.
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