The Cadillac LGU is a 2,997 cc, inline-six turbocharged petrol engine produced from 2019 onwards. It features dual overhead camshafts (DOHC), 24-valve configuration, and General Motors' Dynamic Fuel Management (DFM) system with variable valve timing. In standard tune, it delivers 279 kW (380 PS) at 5,500 rpm and 500 Nm of torque at 2,000–4,000 rpm, offering balanced performance and refinement for luxury applications.
Fitted to models including the CT6 and Lyriq (as a range extender), the LGU was engineered for smooth driving dynamics and responsive power delivery. Emissions compliance was achieved through close-coupled three-way catalytic converters and closed-loop lambda control, meeting Euro 6d standards across its production run.
One documented reliability concern is premature turbocharger wastegate actuator failure, which could lead to boost control issues or engine derate. This issue, highlighted in General Motors Service Information Bulletin 19-06-01-007, is attributed to thermal fatigue in the actuator spring under sustained high load. In 2021, GM introduced a revised actuator with improved heat-resistant materials and recalibrated DFM logic to reduce thermal stress.
Production years 2019–present meet Euro 6d emissions standards (VCA UK Type Approval #VCA/EMS/4004).
The Cadillac LGU is a 2,997 cc inline-six turbocharged petrol engine engineered for full-size luxury and electric-hybrid platforms (2019–present). It combines advanced forced induction with cylinder deactivation to deliver responsive power and improved fuel economy. Designed to meet Euro 6d standards, it balances performance with emissions compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,997 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-6, DOHC, 24-valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 82.6 mm × 92.7 mm | |
| Power output | 279 kW (380 PS) @ 5,500 rpm | |
| Torque | 500 Nm @ 2,000–4,000 rpm | |
| Fuel system | Direct injection with port assist (DPI+) | |
| Emissions standard | Euro 6d | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Single twin-scroll turbocharger with electronic wastegate | |
| Timing system | Double-row roller chain (DOHC) | |
| Oil type | GM dexos1 Gen 3 (SAE 5W-30) | |
| Dry weight | 198 kg |
The turbocharged inline-six delivers smooth, linear power ideal for relaxed cruising but requires strict adherence to 15,000 km oil change intervals to prevent turbo and valvetrain degradation. GM dexos1 Gen 3 (5W-30) oil is critical due to its high-temperature stability and protection for the DPI+ fuel system. Extended idling and short trips increase carbon buildup and oil contamination, accelerating turbo actuator wear. The 2021 update with revised actuator significantly improved durability; pre-2021 engines should verify actuator condition and consider preventative upgrades per GM SIB 19-06-01-007.
Oil Specs: Requires GM dexos1 Gen 3 (5W-30) specification (GM SIB 19 06 01 007). Supersedes dexos1 Gen 2 requirements.
Emissions: Euro 6d certification applies to all LGU models (2019–present) (VCA Type Approval #VCA/EMS/4004).
Power Ratings: Measured under SAE J1349 standards. Output consistent across EU fuel grades (RON 95–98).
General Motors Technical Information System (TIS): Docs A28000, A28001, A28002, SIB 19 06 01 007
VCA Type Approval Database (VCA/EMS/4004)
SAE International: J1349 Engine Power Measurement Standard
The Cadillac LGU was used across Cadillac's CT6/Lyriq platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-increased cooling capacity in the CT6 and revised intake manifolds in the Lyriq-and from 2021 the updated turbocharger actuator with improved heat resistance, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front passenger side of the engine block near the cylinder head (GM TIS A28000). The 8th VIN digit indicates engine family ('G' for LGU series). Pre-2021 models have silver valve covers with black plastic timing covers; post-2021 units use black valve covers. Critical differentiation from LGW: LGU uses a single turbocharged inline-six, while LGW is a twin-turbo V8. Service parts require production date verification - turbo actuators before 09/2021 are incompatible with later revisions due to internal redesign (GM SIB 19 06 01 007).
The LGU's primary reliability risk is turbocharger wastegate actuator failure on early builds, with elevated incidence in vehicles with extended service intervals. Internal GM quality reports from 2022 indicated a significant number of pre-2021 units required actuator replacement before 100,000 km, while UK DVSA records show boost-related faults as a top cause of drivability complaints in Cadillac luxury models. Extended service intervals and use of low-octane fuel increase thermal stress, making fuel quality and schedule adherence critical.
Analysis derived from GM technical bulletins (2019–2023) and UK DVSA failure statistics (2020–2024). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CADILLAC LGU.
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