GM L3B Engine Specs, Problems And Reliability

GM L3B Engine Specs, Problems And Reliability

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By Scott Matthew

Since 2018, the General Motors L3B 2.7-liter V6 engine has been a symbol of precision production at the Tennessee plant. This powerhouse is strategically integrated into both rear-wheel drive and all-wheel drive models, making its mark on vehicles like the Cadillac CT4 and various Chevrolet and GMC pickups.

Derivative Model L2R: An interesting variation of this engine is the L2R, which is derated to 237 hp and 353 Nm. This modification showcases the adaptability of the L3B engine to cater to diverse performance requirements.

Part of the High Feature Engine Family: Belonging to the esteemed High Feature engine family, which includes notable engines like LP9, LF1, LFX, LFY, LGX, LLT, and LY7, the L3B engine stands out for its performance prowess.

Driving Excellence in Various Models

The L3B engine has found its place in several impressive models, delivering a driving experience that combines power and precision. Key installations include:

  • Cadillac CT4 I (A2SL) since 2019
  • Chevrolet Colorado 3 (GMT31XX-2) since 2023
  • Chevrolet Silverado 4 (GMT1RC) since 2018
  • GMC Canyon 3 (GMT31XX-2) since 2023
  • GMC Sierra 5 (GMT1RG) since 2018

High-Performance Legacy: The General Motors L3B engine is not just an assembly of components; it represents a legacy of high-performance engineering. Its presence in a range of vehicles emphasizes its versatility and the commitment of General Motors to delivering excellence on the road.

Engine Specs

Production YearsSince 2018
Displacement, cc2727
Fuel SystemDirect Injection
Power Output, hp310 – 325
Torque Output, Nm472 – 583
Cylinder BlockAluminum V6
Block HeadAluminum 24v
Cylinder Bore, mm92.25
Piston Stroke, mm102
Compression Ratio10.0
FeaturesAFM (Active Fuel Management), SCS (Spark Control System)
Hydraulic LiftersYes
Timing DriveChain
Phase RegulatorDual VVT (Variable Valve Timing)
TurbochargingBorgWarner B03
Recommended Engine Oil5W-30
Engine Oil Capacity, liter5.7
Fuel TypePetrol
Euro StandardsEURO 6
Fuel Consumption, L/100 kmCity: 11.8, Highway: 8.1, Combined: 10.2
Engine Lifespan, km~250,000
Weight, kg165

Note: The specifications provided are for the engine model, and the fuel consumption values are specific to the Cadillac CT4-V 2020 model.

GM L3B Engine Problems

Challenges Associated with the GM L3B Engine and Corresponding Solutions:

  1. Recall for Wiring Harness Issues:
    Problem: Engines from the initial production year were subject to recall due to wiring harness issues.
    Solution: The recall involved the replacement of the wiring harness to address and rectify the problem.
  2. Carbon Deposits on Intake Valves:
    Problem: The engine relies solely on direct injection, leading to carbon deposits on the intake valves over time.
    Solution: Regular maintenance, including valve cleaning procedures, is recommended to mitigate carbon buildup and maintain optimal engine performance.
  3. Sensitivity of Fuel Injectors and Injection Pumps:
    Problem: Fuel injectors and injection pumps exhibit high sensitivity to the quality of gasoline used.
    Solution: Utilizing high-quality gasoline and adhering to recommended fuel specifications can help prevent issues related to fuel system components.
  4. Malfunctions in AFM Cylinder Deactivation System:
    Problem: Complaints have arisen regarding malfunctions in the system responsible for deactivating some of the AFM cylinders.
    Solution: Software updates and regular system checks can be employed to address and rectify any malfunctions in the AFM cylinder deactivation system. Regular maintenance and prompt resolution of reported issues are essential for optimal engine performance.


In summary, the GM L3B engine presents a set of challenges that have been identified and addressed to enhance overall reliability and performance. The recall for wiring harness issues from the initial production year, along with the potential for carbon deposits on intake valves, underscores the importance of regular maintenance practices. Sensitivity to fuel quality emphasizes the need for conscientious fuel choices, while malfunctions in the AFM cylinder deactivation system call for proactive software updates and diligent system checks.

As with any complex machinery, awareness of these challenges, coupled with adherence to recommended maintenance protocols, plays a crucial role in maximizing the longevity and efficiency of the GM L3B engine. By staying informed about potential issues and implementing timely solutions, users can ensure a more satisfactory and trouble-free experience with this engine model.

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