The GM L8T is a 6,162 cc, 90‑degree V8 petrol engine produced from 2020 to present. It features a pushrod valvetrain (OHV), direct fuel injection, and active fuel management (AFM). In standard form for the Silverado/Sierra it delivers 313 kW (420 PS), with peak torque of 623 Nm, providing strong, effortless towing capability.
Fitted to models such as the Chevrolet Silverado 1500 and GMC Sierra 1500, the L8T was engineered for durability, low — end torque, and efficiency in f…
Production years 2020–Present meet EPA Tier 3 standards (EPA Engine Family Code: GMVL8T.20T3).
The GM L8T is a 6,162 cc 90-degree V8 petrol engine engineered for full-size trucks (2020-Present). It combines a robust pushrod design with direct injection and active fuel management to deliver strong, low-end torque and improved fuel efficiency. Designed to meet EPA Tier 3 standards, it balances heavy-duty performance with modern emissions compliance.
| Parameter | Value | Source |
|---|---|---|
Displacement | 6,162 cc | |
Fuel type | Petrol | |
Configuration | 90° V8, OHV, 16-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 103.25 mm × 92.0 mm | |
Power output | 313 kW (420 PS) @ 5,600 rpm | |
Torque | 623 Nm @ 4,100 rpm | |
Fuel system | SIDI (Spark Ignition Direct Injection) | |
Emissions standard | EPA Tier 3 | |
Compression ratio | 10.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | None | |
Timing system | Chain-driven | |
Oil type | GM Dexos1 Gen 3 (SAE 0W-20) | |
Dry weight | 209 kg |
The GM L8T was used across GM's GMT K2XX platform with longitudinal mounting. This engine received platform-specific adaptations-unique engine mounts for the GMC Sierra and specific intake manifolds for the Chevrolet Silverado-creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
The L8T's primary reliability consideration is potential failure of the high-pressure fuel pump (HPFP), a documented service item in GM bulletins. While not universal, GM internal data indicated a notable service rate for this component, making prompt diagnosis and replacement with revised parts critical for maintaining drivability.
Analysis derived from GM technical bulletins (2020-Present) and NHTSA complaint data (2021-2024). 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 L8T is a robust and powerful engine designed for truck duty. Its main long-term considerations are potential HPFP failure and AFM lifter issues. With regular maintenance, including strict oil changes using Dexos1 Gen 3, these engines are expected to reliably exceed 250,000 km. Oil consumption can be a concern on some high-mileage units.
The most frequent issues are potential failure of the high-pressure fuel pump, failure of the Active Fuel Management lifters causing noise and codes, oil consumption due to piston ring wear, and intake manifold gasket vacuum leaks. These are well-documented in GM service information.
The L8T 6.2L V8 is used in the Chevrolet Silverado 1500 (2020-Present) and GMC Sierra 1500 (2020-Present). It is typically the top-tier V8 option for these full-size trucks, offering a balance of power and efficiency.
Yes, the L8T responds very well to tuning. Simple ECU flashes can unlock 25-40 kW of additional power by optimizing timing and fuel maps. More aggressive modifications like a performance intake, exhaust, and camshaft can yield further gains. The engine's internals are strong and can handle significant power increases reliably.
Fuel economy is typical for a 6.2L V8 in a full-size truck. In a 2022 Silverado 1500 4x4, expect around 16.0 L/100km in the city and 11.5 L/100km on the highway, averaging approximately 13.5 L/100km (21 mpg UK) combined. Actual figures vary significantly with payload, terrain, and driving style.
Yes. The L8T is an interference engine. If the timing chain fails or jumps significantly, the pistons can collide with the open valves, causing catastrophic internal engine damage. The timing chain is generally durable, but maintaining proper oil level and quality is crucial.
GM mandates the use of Dexos1 Gen 3-approved 0W-20 full synthetic oil. This specific low-viscosity formulation is critical for protecting the engine, optimizing fuel economy, and ensuring proper operation of the Active Fuel Management system. Change intervals should not exceed 12,000 km or 12 months, whichever comes first.
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
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
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