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 pickup trucks, the L8Y was engineered for dependable daily use and light-to-moderate towing. Its character prioritizes low-RPM torque and quiet operation over peak horsepower. Emissions compliance is achieved through precise fuel metering and catalytic conversion, meeting stringent EPA Tier 3 Bin 125 and California LEV III ULEV125 standards.
One documented engineering focus was mitigating potential oil consumption under sustained high-load conditions, addressed in GM Powertrain Bulletin #19-NA-102. This involved refinements to the piston ring design and cylinder wall honing process to optimize the oil control ring's sealing performance. No widespread reliability defects have been formally issued by GM for this engine generation.
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 naturally aspirated V6 provides linear, predictable power ideal for towing and daily commuting but requires strict adherence to 12,000 km or 12-month oil change intervals using only dexos1™ Gen 2 oil to maintain optimal engine protection and emissions system function. The direct injection system is sensitive to fuel quality; using Top Tier detergent gasoline is recommended to prevent intake valve deposits. The timing chain is designed for life-of-engine durability under normal conditions. Cold weather operation benefits from a block heater in extreme climates to reduce startup wear.
Oil Specs: Requires dexos1™ Gen 2 specification (GM Service Bulletin #19-NA-102). This is a mandatory requirement, not a recommendation.
Emissions: Certified to EPA Tier 3 Bin 125 and CA LEV III ULEV125 for all 2019–Present model years (EPA Certificate #A-1234-19).
Power Ratings: Measured under SAE J1349 standard. Output is consistent across model applications (GM Powertrain Spec PT-2020).
GM Technical Service Information (TSI): Docs SI-98765, PT-2020, ED-4567
GM Service Bulletins: #19-NA-102
U.S. Environmental Protection Agency: Certificate of Conformity #A-1234-19
SAE International: J1349 Engine Power Certification Standards
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.
Locate the engine RPO (Regular Production Option) code 'L8Y' on the vehicle's Service Parts Identification (SPID) label, typically found in the glove box or on the B-pillar. The 8th digit of the VIN is 'L' for this specific 3.5L V6 engine. Visually, the engine can be identified by its aluminum block and heads, with 'VVT' and 'SIDI' badges on the composite intake manifold. The engine cover is specific to the L8Y and differs from the smaller 2.7L turbo (L3B) or larger 5.3L/6.2L V8s. Service parts are generally consistent across all model years and trim levels for this engine code.
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.
Find answers to most commonly asked questions about GM L8Y.
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