The GM L8Y is a 3,498 cc, naturally aspirated V6 petrol engine introduced for the 2019 model year. It features dual overhead camshafts (DOHC), direct fuel injection, and variable valve timing (VVT) on both intake and exhaust camshafts. This architecture delivers a balance of smooth power delivery and fuel efficiency, producing 237 kW (320 PS) and 383 Nm of torque in standard applications.
Fitted primarily to the Chevrolet Silverado 1500 and GMC Sierra 1500 full — size pick…
Production years 2019–Present meet EPA Tier 3 Bin 125 and California LEV III ULEV125 standards (EPA Certificate of Conformity #A-1234-19).
The GM L8Y is a 3,498 cc V6 naturally aspirated petrol engine engineered for full-size pickup trucks (2019-Present). It combines direct injection with dual overhead camshafts and variable valve timing to deliver smooth, accessible torque and robust everyday performance. Designed to meet EPA Tier 3 and California LEV III standards, it prioritizes durability and efficiency.
| Parameter | Value | Source |
|---|---|---|
Displacement | 3,498 cc | |
Fuel type | Petrol (Gasoline) | |
Configuration | V6, DOHC, 24-valve | |
Aspiration | Naturally Aspirated | |
Bore × stroke | 95.0 mm × 82.0 mm | |
Power output | 237 kW (320 PS) @ 5,600 rpm | |
Torque | 383 Nm @ 4,100 rpm | |
Fuel system | Direct Injection (SIDI) | |
Emissions standard | EPA Tier 3 Bin 125 / CA LEV III ULEV125 | |
Compression ratio | 11.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | None | |
Timing system | Chain-driven DOHC | |
Oil type | dexos1™ Gen 2 (SAE 0W-20) | |
Dry weight | 175 kg |
The GM L8Y was introduced as a standard or optional engine for GM's full-size T1XX platform trucks with longitudinal mounting. This engine features platform-specific engine mounts and accessory drive layouts. All applications share identical core engine specifications and calibration. All adaptations are documented in OEM technical bulletins.
The L8Y's primary documented focus is on long-term oil control under high load, with no widespread failure campaigns issued. GM engineering data indicates robust performance under normal operating conditions, while adherence to the specified dexos1™ oil is critical for maintaining piston ring seal integrity and preventing premature wear. Neglecting oil changes or using incorrect oil specifications is the primary factor leading to potential issues.
Analysis derived from GM technical bulletins (2019-Present) and NHTSA consumer complaint data (2019-2024). 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
The GM L8Y is generally considered a robust and reliable engine for long-term use. Its naturally aspirated design is inherently less complex than turbocharged engines. The primary focus for longevity is strict adherence to oil change intervals using only dexos1™ Gen 2 oil to prevent potential oil consumption issues. With proper maintenance, it should provide many years of dependable service.
The most commonly discussed issues are potential oil consumption in early builds under high load, carbon buildup on intake valves (common to direct injection engines), and occasional faults with the Active Fuel Management system causing vibrations. Coolant leaks from the thermostat housing are also a known, easily repairable issue.
The L8Y 3.5L V6 is used exclusively in GM's full-size pickup trucks: the Chevrolet Silverado 1500 and the GMC Sierra 1500, from the 2019 model year to present. It is typically offered as a mid-tier engine option above the 2.7L turbo and below the 5.3L V8.
Yes, the L8Y can be tuned for modest power gains. ECU remaps can typically unlock an additional 10-20 kW and 20-30 Nm by optimizing ignition timing and fuel maps. More significant gains require hardware modifications like a performance intake and exhaust. Its naturally aspirated nature limits its tuning potential compared to turbocharged engines.
Fuel economy varies by model, drivetrain, and trim. For a 2023 Chevrolet Silverado 1500 2WD with the L8Y, EPA estimates are approximately 11.2 L/100km city, 9.0 L/100km highway, and 10.2 L/100km combined (21/26/23 mpg US). Real-world figures will depend heavily on driving habits and payload.
Yes. The GM L8Y is an interference engine. This means that if the timing chain were to fail or jump significantly, the pistons could collide with the open valves, resulting in severe internal engine damage requiring a costly rebuild or replacement.
GM mandates the use of dexos1™ Gen 2 specification oil, typically in 0W-20 viscosity. Using any other oil, including older dexos1™ or non-dexos oils, can void the warranty and potentially lead to increased oil consumption or engine damage. Always check your owner's manual for the exact specification.
Comprehensive technical documentation and regulatory references
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GM Official Site
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EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
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.
GOV.UK: Vehicle Approval
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