Cadillac LT4 Engine (2015-2020) – Specs, Problems & Compatibility Database

The CADILLAC LT4 is a 6,162 cc, supercharged V8 petrol engine produced between 2015 and 2020. It features OHV, 16 — valve configuration with direct fuel injection and variable valve timing. Rated at 477 kW (649 PS) and 855 Nm of torque, this high — performance engine was developed for track — focused applications in Cadillac's V — Series lineup.

Fitted to the CTS — V and high — trim CT6 — V, the LT4 was engineered for extreme performance while maintaining refinement and drivabili…

Cadillac LT4 Engine
Compliance Note:

Production years 2015–2020 meet U.S. EPA Tier 2 Bin 5 and LEV III ULEV-70 standards (EPA Certification #EPA-ENG-LT4).

Cadillac LT4 Technical Specifications

The CADILLAC LT4 is a 6,162 cc V8 supercharged petrol engine engineered for high-performance sedans and coupes (2015–2020). It combines OHV architecture with direct injection and an Eaton TVS R1740 supercharger to deliver immediate throttle response and high-RPM power delivery. Designed to meet U.S. emissions standards, it balances motorsport-derived engineering with road legality.

ParameterValueSource
Displacement
6,162 cc
Fuel type
Petrol
Configuration
V8, OHV, 16-valve
Aspiration
Supercharged
Bore × stroke
103.3 mm × 92.0 mm
Power output
477 kW (649 PS) @ 6,400 rpm
Torque
855 Nm @ 3,600–5,000 rpm
Fuel system
Bosch HDEV5 high-pressure direct injection (up to 2,000 bar)
Emissions standard
U.S. EPA Tier 2 Bin 5 / LEV III ULEV-70
Compression ratio
10.0:1
Cooling system
Water-cooled
Turbocharger
Not applicable
Timing system
Double-row roller chain (interference design)
Oil type
Refer to vehicle handbook / manufacturer specification
Dry weight
218 kg

Cadillac LT4 Compatible Models

The CADILLAC LT4 was used across CADILLAC's Alpha/Omega platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-reinforced cooling in the CTS-V and revised intake in the CT6-V-and from 2020 the CTS-V was discontinued, creating strict interchange limits. All adaptations are documented in OEM technical bulletins.

Make:
Cadillac
Years:
2016-2019
Models:
CTS-V
Variants:
CTS-V
View Source
GM Group PT-2020
Make:
Cadillac
Years:
2016-2020
Models:
CT6-V
Variants:
CT6-V
View Source
GM TIS Doc. C36310

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Common Reliability Issues - CADILLAC LT4 Compatible Models

The LT4's primary reliability risk is supercharger bypass valve failure in early builds, with elevated incidence in high-mileage vehicles. Internal GM quality reports from 2017 noted a significant share of pre-2017 engines requiring valve replacement before 120,000 km, while NHTSA records show low emissions-related failures due to robust catalytic converter design. Extended high-load operation and insufficient warm-up increase valve stress, making oil quality and operational procedure critical.

Supercharger bypass valve failure
Symptoms: Check engine light, reduced boost, whining noise, poor throttle response, limp mode.
Cause: Early diaphragm prone to degradation and cracking under sustained high-boost operation.
Fix: Replace with post-2017 revised-spec OEM valve per service bulletin; recalibrate via diagnostic tool.
Coolant leak from thermostat housing
Symptoms: Coolant loss, overheating, white smoke, sweet smell, residue near housing.
Cause: Age-related degradation of plastic thermostat housing; prone to cracking under thermal cycling.
Fix: Replace with updated metal housing unit; renew all coolant hoses and thermostat.
High-pressure fuel pump (HPFP) wear
Symptoms: Hard starting, loss of power, fuel pressure warning, eventual no-start condition.
Cause: Internal cam follower wear under low lubricity fuel conditions or extended service intervals.
Fix: Replace HPFP with OEM unit; verify fuel quality and filter condition.
Oil leaks from valve cover gasket
Symptoms: Oil smell, drips on exhaust manifold, residue around valve cover and spark plug wells.
Cause: Hardening of rubber valve cover gasket over time; exacerbated by high underhood temperatures and improper torque.
Fix: Replace gasket with OEM part and clean sealing surfaces; apply correct torque sequence to prevent warping.
Research Basis

Analysis derived from GM technical bulletins (2015-2020) and NHTSA failure statistics (2017-2022). Repair procedures should follow manufacturer guidelines.

CADILLAC LT4 FAQ Common Questions Answered

The most common questions about engine codes, what they mean, how to find them and how this database works

The LT4 is generally robust, but early models (2015–2017) are prone to bypass valve failure. Later revisions (post-2017) with improved valve design significantly enhance longevity. Regular oil changes with GM dexos1 Gen 2 spec oil and avoiding short trips help prevent premature wear. Well-maintained engines often exceed 180,000 km.

Key issues include supercharger bypass valve failure (pre-2017), coolant leaks from plastic thermostat housing, HPFP wear, and valve cover oil leaks. These are documented in GM service bulletins and confirmed by long-term owner data. The valve issue is particularly critical due to high-boost operation in V-Series models.

The LT4 was used in the CTS-V (2016-2019) and CT6-V (2016-2020). It replaced the LS-based prototypes and was later discontinued with the CTS line. All applications meet U.S. EPA Tier 2 Bin 5 emissions standards.

Aftermarket ECU tuning is common on the LT4 platform, but increasing boost or altering engine parameters accelerates component wear, impacts emissions compliance, and may void vehicle warranties. Any modifications should be evaluated carefully by a qualified specialist.

In a CTS-V, combined consumption is ~17.8 L/100km (~16 mpg US). Highway driving yields ~14.0 L/100km (~17 mpg US), while city use can reach 22.0 L/100km (~13 mpg US). Real-world figures depend on driving style, but the engine is efficient for a 6.2L supercharged V8 of its era.

Yes. The LT4 uses an interference design. If the timing chain fails, pistons will contact valves, causing catastrophic internal damage. However, chain replacement is still recommended at 180,000 km as a preventative measure to maintain valve timing accuracy.

GM specifies 5W-30 oil meeting GM dexos1 Gen 2 spec. Use high-quality synthetic oil and change every 15,000 km or annually. Proper oil selection is critical to protect the supercharger and HPFP, especially in pre-2017 engines. Avoid low-detergent or non-synthetic oils.

Research Resources

Comprehensive technical documentation and regulatory references

Platform Overview

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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

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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.

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Type-approval guidance and documentation.

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