The GM L8 is a 3,498 cc, naturally aspirated V6 petrol engine produced from 2020 onwards. It features dual overhead camshafts (DOHC), direct fuel injection, and variable valve timing (VVT) to deliver a balance of power and refinement. Peak output is rated at 237 kW (320 PS) and 383 Nm of torque, providing strong mid-range pull for confident overtaking.
Fitted primarily to the Chevrolet Blazer and Cadillac XT4, the L8 was engineered for responsive, everyday performance in mid-size SUVs. Its character emphasizes smooth power delivery and quiet operation. Emissions compliance is achieved through its advanced combustion system and three-way catalytic converter, meeting stringent Euro 6d and U.S. Tier 3 Bin 30 standards.
One documented engineering focus is managing oil consumption under sustained high-load conditions, addressed in GM Service Bulletin #21-NA-305. This bulletin outlines revised piston ring specifications and updated engine control module (ECM) calibration for affected production batches to optimize ring sealing.
Production years 2020–Present meet Euro 6d and U.S. Tier 3 Bin 30 standards (EPA Certificate of Conformity #A-20-001).
The GM L8 is a 3,498 cc V6 naturally aspirated petrol engine engineered for mid-size SUVs (2020-Present). It combines direct injection with variable valve timing to deliver smooth, responsive power and quiet operation. Designed to meet Euro 6d and U.S. Tier 3 Bin 30 standards, it balances performance with stringent emissions control.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,498 cc | |
| Fuel type | Petrol | |
| Configuration | V6, DOHC, 24-valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 95.0 mm × 82.0 mm | |
| Power output | 237 kW (320 PS) @ 6,700 rpm | |
| Torque | 383 Nm @ 5,000 rpm | |
| Fuel system | Direct Injection (SIDI) | |
| Emissions standard | Euro 6d / U.S. Tier 3 Bin 30 | |
| Compression ratio | 11.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven | |
| Oil type | dexos1™ Gen 3 (SAE 5W-30) | |
| Dry weight | 168 kg |
The naturally aspirated design offers linear power delivery and low mechanical complexity but requires premium unleaded fuel (91+ AKI) for optimal performance and to prevent knock. Strict adherence to 12,000 km or 12-month oil changes using dexos1™ Gen 3 oil is critical for maintaining variable valve timing system health and preventing carbon buildup. The direct injection system necessitates periodic intake valve cleaning to maintain airflow and idle quality. Revised piston rings per GM SIB #21-NA-305 are recommended for high-mileage or high-load applications to mitigate potential oil consumption.
Oil Specs: Requires GM dexos1™ Gen 3 specification (GM Service Manual SI-9987). This is a mandatory requirement, not a recommendation.
Emissions: Certified to Euro 6d and U.S. Tier 3 Bin 30 standards (EPA Certificate of Conformity #A-20-001). Applies to all model years 2020–Present.
Power Ratings: Measured under SAE J1349 standards. Peak output requires 91 AKI (RON 95) or higher fuel (GM Owner's Manual).
GM Technical Information System (TIS): Docs SI-9987, #20-V6-001, #21-NA-305
GM Electronic Parts Catalog (EPC): Doc. ENG-8876
U.S. Environmental Protection Agency (EPA) Certificate Database (A-20-001)
SAE International: J1349 Engine Power Certification Standards
The GM L8 was used across GM's Theta platform SUVs with transverse mounting and no external licensing. This engine received platform-specific adaptations-unique engine mounts and accessory drive layouts for the Blazer versus the XT4-creating minor service part differences. All adaptations are documented in OEM technical bulletins.
Locate the engine code 'L8' stamped on a machined pad on the front of the engine block, near the timing cover (GM TIS Doc. ENG-ID-008). The 8th digit of the VIN is 'L' for vehicles equipped with this engine. Visually, it can be identified by its aluminum block and heads, and the 'V6 3.5L' badge on the engine cover. Critical differentiation from the turbocharged L3B: The L8 lacks a turbocharger, intercooler, and associated plumbing. Service parts like intake manifolds and exhaust manifolds are specific to the Blazer or XT4 application and are not interchangeable (GM SIB #22-INT-011).
The L8's primary documented service focus is potential oil consumption on early builds, with elevated incidence under sustained high-RPM driving. GM internal data from 2021 indicated a subset of pre-mid-2021 engines required piston ring updates, while NHTSA data shows no significant safety recalls. High-load driving cycles make adherence to the revised service procedure critical.
Analysis derived from GM technical bulletins (2020-2023) and NHTSA recall data (2020-2024). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about GM L8.
Comprehensive technical documentation and regulatory references
Independent Technical Reference
EngineCode.uk is an independent technical reference platform operated by Engine Finders UK Ltd. We are not affiliated with GM or any other manufacturer. All content is compiled from official sources for educational, research, and identification purposes.
Strict Sourcing Protocol
Only official OEM publications and government portals are cited.
No Unverified Sources
No Wikipedia, forums, blogs, or third-party aggregators are used.
Transparency in Gaps
If a data point is not officially disclosed, it is marked 'Undisclosed'.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
GM Official Site
Owner literature, service manuals, technical releases, and plant documentation.
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
Type-approval guidance and documentation.
Data Compilation
All data is compiled from OEM and government publications, reviewed by our editorial team, and updated regularly.
Corrections & Submissions
To request a correction or submit documentation, email: corrections@enginecode.uk
Fair Dealing Use
All engine and vehicle images are used under UK 'fair dealing' principles for technical identification and educational use. Rights remain with their respective owners.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
GDPR Compliance
EngineCode.uk complies with UK GDPR. We do not collect personal data unless explicitly provided.
Data Requests
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
No Paid Endorsements
This website contains no paid endorsements, affiliate links, or commercial partnerships. We do not sell parts or services.
Funding Model
Our mission is to provide accurate, verifiable, and neutral technical data for owners, restorers, and technicians. This site is self-funded.
All specifications and compatibility data verified against officialGM documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed“ .
All external links open in new tabs. Please verify current availability of resources.
