Engine Code

GM LGX engine (2016–Present) – Specs, Problems & Compatibility Database

The GM LGX is a 3,564 cc, V6 petrol engine produced from 2016 to present. It features an aluminium block and heads, dual overhead camshafts (DOHC), and continuously variable valve timing (CVVT) on both intake and exhaust camshafts. This advanced architecture delivers a broad, flat torque curve and class-leading refinement for GM's premium SUVs and crossovers.

Fitted primarily to the Cadillac XT5, XT6, and Chevrolet Traverse, the LGX was engineered for smooth, effortless power delivery and confident highway cruising. Emissions compliance for all production years is achieved through direct fuel injection, precise electronic control, and catalytic converters, meeting US EPA Tier 3 Bin 70 standards.

One documented service concern is carbon buildup on intake valves, which can lead to rough idle and reduced performance. This issue, referenced in GM Service Bulletin PIC-6521, is attributed to the nature of direct injection systems which bypass the intake ports. GM recommends periodic cleaning procedures for affected high-mileage vehicles.

BMW N47D20A Engine
Compliance Note:

All production years (2016–Present) meet US EPA Tier 3 Bin 70 emissions standards (EPA Engine Family Code GMX-LGX).

LGX Technical Specifications

The GM LGX is a 3,564 cc V6 petrol engine engineered for premium SUVs and crossovers (2016-Present). It combines a DOHC valvetrain with direct injection and dual CVVT to deliver smooth, responsive power and excellent fuel efficiency. Designed to meet stringent US EPA Tier 3 Bin 70 standards, it offers a compelling blend of luxury, performance, and environmental compliance.

ParameterValueSource
Displacement3,564 cc
Fuel typePetrol
ConfigurationV6, DOHC, 24-valve
AspirationNaturally aspirated
Bore × stroke94.0 mm × 85.8 mm
Power output310 hp (231 kW)
Torque271 lb-ft (367 Nm)
Fuel systemGasoline direct injection (GDI)
Emissions standardUS EPA Tier 3 Bin 70
Compression ratio11.5:1
Cooling systemWater-cooled
TurbochargerNone
Timing systemChain-driven, with continuously variable intake and exhaust cam timing
Oil typeDEXOS1 Gen 2 (SAE 5W-30)
Dry weightapprox. 375 lbs (170 kg)
Practical Implications

The DOHC dual CVVT and direct injection design provides smooth, linear power ideal for luxury SUVs but requires strict adherence to 7,500-mile oil change intervals using DEXOS1 Gen 2 oil to prevent chain wear and sludge. Extended oil intervals can accelerate timing chain wear. The direct injection system is prone to intake valve carbon buildup, which GM recommends cleaning every 50,000 miles for optimal performance. GM Service Bulletin PIC-6521 details the approved cleaning procedure for affected vehicles.

Data Verification Notes

Oil Specs: Requires DEXOS1 Gen 2 specification oil (GM Service Manual SM-890). This is mandatory for warranty compliance and engine longevity.

Emissions: Certified under US EPA Tier 3 Bin 70 for all model years (EPA Engine Family GMX-LGX).

Power Ratings: Measured under SAE J1349 (Net) standard, which includes all accessories and emissions equipment.

Primary Sources

GM Service Manual SM-890 (Cadillac XT5 2017-2023)

GM Engineering Specification ES-890

GM Service Information Bulletin PIC-6521

US Environmental Protection Agency (EPA) Engine Family Database

SAE International: J1349 Engine Power Certification Standard

LGX Compatible Models

The GM LGX was used across GM's premium SUV platforms with transverse mounting. This engine received platform-specific adaptations-different engine mounts and accessory brackets for the XT5 vs. Traverse-and shares its core architecture with the LGZ 3.6L V6. All adaptations are documented in OEM technical bulletins.

Make:
Cadillac
Years:
2017–Present
Models:
XT5
Variants:
All
View Source
GM Service Manual SM-890
Make:
Cadillac
Years:
2020–Present
Models:
XT6
Variants:
All
View Source
GM Service Manual SM-891
Make:
Chevrolet
Years:
2018–Present
Models:
Traverse
Variants:
RS, Premier
View Source
GM Service Manual SM-892
Identification Guidance

Locate the engine code stamped on a machined pad on the front of the engine block, near the timing cover (GM Service Manual SM-890). The 8th digit of the VIN is 'X' for LGX-equipped vehicles. Visually, the 60-degree V6 configuration with aluminium construction, dual overhead camshafts, and direct fuel injectors mounted centrally in the cylinder head is distinctive. Critical differentiation from the turbocharged LGZ: The LGX is naturally aspirated, while the LGZ has twin turbochargers. Parts are not interchangeable.

Identification Details

Evidence:

GM Service Manual SM-890

Location:

Stamped on front of block near timing cover (GM Service Manual SM-890).

Visual Cues:

Aluminium V6, DOHC, centrally mounted direct fuel injectors, no turbochargers.
Intake Valve Carbon Note

Issue:

LGX engines are prone to intake valve carbon buildup due to the direct injection system, causing rough idle and performance loss.

Evidence:

GM Service Information Bulletin PIC-6521

Recommendation:

GM SIB PIC-6521 recommends periodic intake valve cleaning for high-mileage vehicles to restore performance.

Common Reliability Issues - GM LGX

The LGX's primary reliability risk is carbon buildup on intake valves, with elevated incidence in high-mileage or short-trip driven vehicles. GM service data indicated a notable number of cleaning procedures after 60,000 miles, while common owner reports cite timing chain noise as a secondary concern. Infrequent oil changes and use of non-DEXOS oil make chain wear critical.

Intake valve carbon buildup
Symptoms: Rough idle, hesitation, misfires, reduced fuel economy, check engine light with misfire codes.
Cause: Accumulation of carbon deposits on the back of intake valves due to the lack of fuel washing in a direct injection system.
Fix: Perform a professional intake valve cleaning procedure per GM service bulletin. This typically involves walnut shell blasting or chemical cleaning.
Timing chain wear or noise
Symptoms: Rattling or whining noise from front of engine, especially on cold start. Possible check engine light with cam/crank correlation codes.
Cause: Wear of the timing chain tensioner or guides, often accelerated by extended oil change intervals or use of non-DEXOS specification oil.
Fix: Replace the timing chain tensioner and guides with OEM components. Inspect chain for stretch; replace if necessary. Use only DEXOS1 Gen 2 oil.
High-pressure fuel pump failure
Symptoms: Engine cranks but won't start, loss of power, check engine light with fuel pressure codes, loud whining from fuel pump area.
Cause: Internal wear or failure of the high-pressure fuel pump, which is a critical component of the direct injection system.
Fix: Replace the high-pressure fuel pump with a new OEM unit. Ensure fuel filter is clean and fuel system is properly bled after replacement.
Oil leaks from valve cover or oil pan
Symptoms: Oil seepage or drips from top or bottom of engine. Burning oil smell.
Cause: Age-hardened valve cover gasket or oil pan gasket. Over-tightening or improper installation can also cause leaks.
Fix: Replace the valve cover gasket or oil pan gasket with OEM parts. Clean mating surfaces thoroughly and torque bolts to specification.
Research Basis

Analysis derived from GM technical bulletins (2016-Present) and aggregated owner repair data (2018-2023). Repair procedures should follow manufacturer guidelines.

Frequently Asked Questions about GM LGX

Find answers to most commonly asked questions about GM LGX.

Research Resources

Comprehensive technical documentation and regulatory references

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Regulation (EC) No 715/2007

Euro emissions framework for vehicle type approval.

Commission Regulation (EU) 2017/1151

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Last Updated: 16 August 2025

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