The Chevrolet LZ8 is a 3,900 cc, V6 gasoline engine produced between 2007 and 2011. It features a 60-degree overhead valve (OHV) design with variable valve timing (VVT) and sequential fuel injection. Designed for light-duty trucks and SUVs, it delivers 211 kW (285 PS) and 373 Nm of torque, providing strong mid-range performance for daily driving and towing applications.
Fitted to models such as the Chevrolet TrailBlazer, GMC Envoy XL, and Saab 9-7X, the LZ8 was engineered for balanced performance, refinement, and fuel efficiency in full-size SUV applications. Emissions compliance was achieved through a three-way catalytic converter and exhaust gas recirculation (EGR), allowing the engine to meet U.S. Tier 2 Bin 5 and corresponding Euro 4 standards in export markets.
One documented concern is intake manifold runner control (IMRC) actuator failure, highlighted in GM Service Bulletin 07-06-04-007. Faulty actuators can cause reduced airflow, rough idle, and check engine lights due to vacuum leaks or stuck flaps. Later production runs incorporated revised plastic gears within the actuator assembly to improve durability.
Chevrolet
Production years 2007–2009 meet U.S. Tier 2 Bin 5 and Euro 4 standards; 2010–2011 models comply with enhanced evaporative emissions requirements (EPA Doc. EPA-HQ-OAR-2005-0075).
The Chevrolet LZ8 is a 3,900 cc V6 gasoline engine engineered for full-size SUVs and trucks (2007-2011). It combines a compact 60° OHV architecture with variable valve timing to deliver responsive mid-range torque and smooth operation. Designed to meet U.S. Tier 2 and Euro 4 emissions standards, it balances performance with everyday drivability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,900 cc | |
| Fuel type | Gasoline | |
| Configuration | 60° V6, OHV, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 100.0 mm × 82.0 mm | |
| Power output | 211 kW (285 PS) @ 5,600 rpm | |
| Torque | 373 Nm @ 4,400 rpm | |
| Fuel system | Sequential port fuel injection (SFI) | |
| Emissions standard | U.S. Tier 2 Bin 5 / Euro 4 | |
| Compression ratio | 10.1:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Double roller chain (cam-to-crank) | |
| Oil type | GM Dexos1 5W-30 | |
| Dry weight | 185 kg |
The OHV V6 design provides smooth, linear power delivery ideal for towing and highway cruising but requires strict adherence to 15,000 km oil change intervals to protect the variable valve timing (VVT) phaser and timing chain. GM Dexos1 5W-30 oil is essential to maintain proper oil pressure and prevent VVT rattle. Extended idling or short-trip driving can accelerate carbon buildup on intake valves. The IMRC system demands periodic inspection to prevent actuator gear wear. Use of ethanol-blended fuels above E10 may degrade fuel system seals over time. Post-2009 models feature revised IMRC actuators; earlier units should be inspected for cracking or gear stripping.
Oil Specs: Requires GM Dexos1 5W-30 specification (GM SIB 07-06-01-003). Supersedes API SM/ILSAC GF-4.
Emissions: Tier 2 Bin 5 applies to all U.S.-spec models (EPA Certification #EPA/ENG/3900LZ8). Export models meet Euro 4 per EU Regulation (EC) No 715/2007.
Power Ratings: Measured under SAE J1349 standards. Output assumes 87 AKI (RON 91) fuel; higher octane does not increase output.
General Motors Technical Information System (TIS): Docs V6X-3900A, FUEL-3900, SIB 07-06-04-007
EPA Engine Certification Database (EPA/ENG/3900LZ8)
SAE International: J1349 Engine Power Certification Standards
The Chevrolet LZ8 was used across GM's GMT360 platform with longitudinal mounting and shared with Saab and Isuzu under corporate partnerships. This engine received platform-specific calibrations-adapted throttle response in the TrailBlazer SS and revised torque curves in the Saab 9-7X Aero-and from 2009 received updated IMRC actuators, creating interchange limits. Partnerships allowed Saab to badge the LZ8 as the "V6 3.9i" in North American markets. All adaptations are documented in OEM technical bulletins.
Locate the engine ID code stamped on the passenger-side front cylinder block near the exhaust manifold (GM TIS V6X-3900A). The 8th VIN digit indicates engine type ('T' for LZ8). Pre-2009 models have black valve covers with silver GM emblems; post-2009 units use revised IMRC actuators with ribbed housing. Critical differentiation from LL8: LZ8 features variable valve timing (VVT) phaser on the front camshaft, visible as a cylindrical actuator behind the timing cover. Service parts require production date verification - IMRC actuators before 08/2008 are incompatible with later units due to internal gear redesign (GM SIB 07-06-04-007).
The LZ8's primary reliability risk is intake manifold runner control (IMRC) actuator failure, with elevated incidence in high-heat climates and stop-start driving. GM internal field reports from 2010 indicated over 15% of pre-2009 units required IMRC service before 160,000 km, while NHTSA data links a notable share of P2015 DTCs to this issue. Extended oil intervals and ethanol-blended fuels increase VVT and actuator wear, making fluid quality and maintenance adherence critical.
Analysis derived from GM technical bulletins (2007-2011) and NHTSA field reports (2008-2013). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CHEVROLET LZ8.
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