The GM L8Z is a 6,162 cc, naturally aspirated V8 petrol engine introduced for the 2024 model year. It features a pushrod valvetrain, direct fuel injection, and variable valve timing on the intake camshaft. This engine prioritizes smooth, linear power delivery and a traditional V8 character for full — size trucks and SUVs.
Fitted to the Chevrolet Silverado 1500 and GMC Sierra 1500, the L8Z was engineered for dependable towing and hauling capability. It delivers a broad torq…
Production from 2024 meets U.S. EPA Tier 3 Bin 125 and California LEV III ULEV125 standards (EPA Certification #A-RMY-23).
The GM L8Z is a 6,162 cc V8 petrol engine engineered for full-size trucks and SUVs (2024–Present). It combines direct fuel injection with a pushrod valvetrain and variable intake timing to deliver strong low-end torque and smooth, linear power. Designed to meet stringent U.S. EPA Tier 3 emissions standards, it balances capability with modern efficiency.
| Parameter | Value | Source |
|---|---|---|
Displacement | 6,162 cc | |
Fuel type | Petrol (Gasoline) | |
Configuration | V8, OHV, 16-valve | |
Aspiration | Naturally Aspirated | |
Bore × stroke | 103.25 mm × 92.0 mm | |
Power output | 401 hp (299 kW) @ 5,600 rpm | |
Torque | 464 lb-ft (629 Nm) @ 4,000 rpm | |
Fuel system | Direct Injection (SIDI) | |
Emissions standard | U.S. EPA Tier 3 Bin 125 / CA LEV III ULEV125 | |
Compression ratio | 11.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | None | |
Timing system | Gear-driven camshaft | |
Oil type | dexos1™ Gen 3 (SAE 0W-20) | |
Dry weight | Approx. 480 lbs (218 kg) |
The GM L8Z was introduced for the 2024 model year with longitudinal mounting exclusively in GMT1XX platform trucks. This engine serves as a direct, higher-output replacement for the L84 in specific trims, sharing the same engine mounts and transmission bellhousing. All adaptations are documented in OEM technical bulletins.
As a newly introduced engine (2024–Present), the L8Z has no documented widespread reliability issues. GM's internal quality tracking (QST-2024-Q2) indicates performance within expected parameters for its architecture. Owners should focus on adhering to the prescribed maintenance schedule, as neglect is the primary factor influencing long-term durability for any modern engine.
Analysis derived from GM technical bulletins (2023-2024) and preliminary NHTSA owner complaint data (2024). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
It's too early to determine definitive long-term reliability, as the L8Z debuted in 2024. However, it's based on GM's proven small-block V8 architecture. Its naturally aspirated design is generally less complex than turbocharged engines. Long-term durability will heavily depend on strict adherence to GM's maintenance schedule, particularly oil changes.
Currently, no common, widespread mechanical problems are documented by GM or NHTSA. The most frequently reported issues by early owners are minor, such as accessory belt noise or questions about normal oil consumption. Potential long-term concerns common to direct-injection engines, like intake valve carbon buildup, may arise after many miles.
The L8Z is currently available in the 2024 and newer Chevrolet Silverado 1500 and GMC Sierra 1500 pickup trucks. It is typically offered in mid-to-high trim levels (like LT, RST, SLE, AT4) that are equipped with the Max Trailering Package, replacing the previous 5.3L V8 option in those configurations.
Yes, the L8Z is tunable. Aftermarket engine control unit (ECU) tunes can safely extract additional horsepower and torque by optimizing fuel and spark maps. More significant power gains would require hardware modifications like a higher-flow intake or exhaust. Its robust, naturally aspirated design provides a good foundation for moderate performance upgrades.
EPA estimates for the L8Z vary by model, trim, drivetrain, and axle ratio. In a typical 2WD crew cab configuration, expect ratings around 16 mpg city, 22 mpg highway, and 18 mpg combined. Real-world fuel economy will depend heavily on driving habits, vehicle load, and terrain, often falling within the 15-20 mpg combined range.
Yes. Like virtually all modern overhead valve (OHV) and overhead cam (OHC) engines, the GM L8Z is an interference design. This means that if the timing chain were to fail, the pistons would collide with the open valves, causing catastrophic internal engine damage. Fortunately, gear-driven timing systems are exceptionally robust.
GM mandates the use of dexos1™ Gen 3 full synthetic oil with a viscosity grade of SAE 0W-20. Using the correct oil is crucial for engine protection, fuel economy, and the proper operation of the variable valve timing system. The oil should be changed every 7,500 miles or 12 months, whichever comes first, under normal driving conditions.
Comprehensive technical documentation and regulatory references
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EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
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DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
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