The GM LH6 is a 5,328 cc, naturally aspirated V8 petrol engine produced between 2007 and 2009. It features overhead valve (OHV) architecture with two valves per cylinder and variable valve timing (VVT) on the exhaust camshaft. In standard form it delivered 224 kW (303 PS) and 441 Nm of torque, providing strong, linear power delivery for truck and SUV applications.
Fitted to models such as the Chevrolet TrailBlazer SS, Saab 9 — 7X, and GMC Envoy Denali, the LH6 was engineered fo…
Production years 2007–2009 meet U.S. Tier 2 Bin 5 and Euro 4 standards (EPA Certificate of Conformity #A-07-001).
The GM LH6 is a 5,328 cc V8 naturally aspirated petrol engine engineered for full-size SUVs and trucks (2007-2009). It combines OHV architecture with exhaust-only variable valve timing to deliver strong, low-RPM torque and confident towing performance. Designed to meet U.S. Tier 2 Bin 5 and Euro 4 standards, it balances power with emissions control.
| Parameter | Value | Source |
|---|---|---|
Displacement | 5,328 cc | |
Fuel type | Petrol | |
Configuration | V8, OHV, 16-valve | |
Aspiration | Naturally Aspirated | |
Bore × stroke | 96.0 mm × 92.0 mm | |
Power output | 224 kW (303 PS) @ 5,200 rpm | |
Torque | 441 Nm @ 4,000 rpm | |
Fuel system | Sequential Multi-Port Fuel Injection (SFI) | |
Emissions standard | U.S. Tier 2 Bin 5 / Euro 4 | |
Compression ratio | 9.9:1 | |
Cooling system | Water-cooled | |
Turbocharger | None | |
Timing system | Chain-driven | |
Oil type | dexos1™ (SAE 5W-30) | |
Dry weight | 209 kg |
The GM LH6 was used across GM's GMT360 platform SUVs with longitudinal mounting and no external licensing. This engine received platform-specific adaptations-unique engine mounts and accessory drive layouts for the TrailBlazer SS versus the Envoy Denali-creating minor service part differences. All adaptations are documented in OEM technical bulletins.
The LH6's primary documented service focus is potential oil consumption under high-load conditions, with elevated incidence in towing or performance applications. GM internal data from 2008 indicated a subset of engines required piston ring updates, while NHTSA data shows no significant safety recalls. High-load driving cycles make adherence to the revised service procedure critical.
Analysis derived from GM technical bulletins (2006-2009) and NHTSA recall data (2006-2009). Repair procedures should follow manufacturer guidelines.
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The GM LH6 is generally robust, with its simple OHV design and lack of forced induction reducing complexity. The primary concern is oil consumption under high load, which is addressed by a factory service bulletin. With regular maintenance using dexos1™ oil and attention to the VVT system, it should provide dependable long-term service, especially in non-towing applications.
The most common documented issues are excessive oil consumption (under high load), VVT actuator failure due to oil sludge, intake manifold gasket leaks, and knock sensor failure. These are addressed in GM service bulletins and are generally manageable with proper maintenance.
The LH6 engine was found in the Chevrolet TrailBlazer SS, GMC Envoy Denali, and Saab 9-7X Aero from the 2006 to 2009 model years. It was not used in any other GM vehicles or beyond the 2009 model year.
Yes, the LH6 responds well to tuning. An ECU remap can yield gains of 15-25 kW by optimizing ignition and fuel maps. Bolt-on modifications like a performance exhaust and cold air intake can add further gains. Significant power increases require internal modifications like a performance camshaft.
Fuel economy is typical for a 5.3L V8 of its era. In a Chevrolet TrailBlazer SS, expect around 16.8 L/100km (city) and 11.8 L/100km (highway), or approximately 16 mpg (US) combined. Real-world figures vary significantly based on driving style and vehicle weight.
No. The GM LH6 is a non-interference engine. If the timing chain were to fail, the pistons would not contact the open valves, preventing catastrophic internal damage. The engine would simply stop running, requiring a timing chain replacement.
GM mandates the use of dexos1™ full synthetic oil, typically in 5W-30 viscosity. Using the correct specification is critical for the health of the variable valve timing system and to minimize oil consumption. This is non-negotiable for warranty compliance and engine longevity.
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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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