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 full-size truck applications. Emissions compliance is achieved through precise direct injection and advanced catalytic converters, meeting stringent EPA Tier 3 standards for its production run.
One documented concern is potential failure of the high-pressure fuel pump (HPFP), which can lead to drivability issues. This issue, highlighted in GM Service Bulletin 21‑06‑01‑001, is often linked to internal wear or contamination. GM recommends inspection and replacement if symptoms arise, using only the latest revised pump assembly.
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 pushrod design and direct injection provide strong, low-RPM torque ideal for towing but require strict adherence to 12,000 km oil change intervals using GM Dexos1 Gen 3 to protect the AFM system and timing chain. The 0W-20 viscosity is critical for optimal fuel economy and component protection. The high-pressure fuel pump is a known service item; any drivability issues should prompt immediate diagnosis per GM SIB 21-06-01-001. The ECU is calibrated for 87 RON fuel.
Oil Specs: Requires GM Dexos1 Gen 3 (0W-20) specification (GM SIB 21-06-01-001).
Emissions: EPA Tier 3 certification applies to all 2020–Present models (EPA Engine Family Code: GMVL8T.20T3).
Power Ratings: Measured under SAE J1349 standards. Rated for 87 RON fuel (GM Service Manual SI-H2000A).
GM Technical Service Information: Docs SI-H2000A, 21-06-01-001
EPA Engine Family Database (GMVL8T.20T3)
SAE International: J1349 Engine Power Certification Standards
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.
Locate the engine code stamped on the front of the engine block, near the timing cover (GM Service Manual SI-H2000A). The 8th VIN digit for L8T-equipped vehicles is typically 'T'. The engine can be visually identified by its direct injection fuel rails and “V8” badge on the plastic engine cover. Critical differentiation from the L83 5.3L: L8T has a larger displacement (6.2L vs 5.3L) and unique cylinder head casting. ECU software is specific to model and year.
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.
Find answers to most commonly asked questions about GM L8T.
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