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 drivability. Emissions compliance was achieved through close-coupled three-way catalytic converters and secondary air injection system, meeting U.S. EPA Tier 2 Bin 5 and LEV III ULEV-70 standards for its production run.
One documented reliability concern is premature supercharger bypass valve failure, particularly in early production units before 2017. This issue, referenced in General Motors Service Information Bulletin 17-NA-022, is attributed to diaphragm degradation under sustained high-boost operation. In 2017, GM revised the valve design, improving durability in later models.
Production years 2015–2020 meet U.S. EPA Tier 2 Bin 5 and LEV III ULEV-70 standards (EPA Certification #EPA-ENG-LT4).
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.
| Parameter | Value | Source |
|---|---|---|
| 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 | GM dexos1 Gen 2 (SAE 5W-30) | |
| Dry weight | 218 kg |
The supercharged V8 delivers extreme performance ideal for track and spirited driving but requires adherence to 15,000 km oil change intervals to prevent supercharger and bearing wear. GM dexos1 Gen 2 (5W-30) oil is essential due to its thermal stability and protection for the supercharger internals. Extended high-load operation or insufficient warm-up increases stress on the bypass valve in pre-2017 engines. The Bosch HDEV5 ECU is robust but sensitive to fuel quality; always use premium unleaded (RON 91+). Post-2017 models feature revised bypass valves per GM SIB 17-NA-022, significantly enhancing long-term reliability.
Oil Specs: Requires GM dexos1 Gen 2 specification (GM SIB 17-NA-022). API SP/ILSAC GF-6 compatible oils acceptable.
Emissions: EPA Tier 2 Bin 5 certification applies to all models (2015–2020) (EPA Type Approval #EPA-ENG-LT4).
Power Ratings: Measured under SAE J1349 standards. Output consistent across fuel qualities (GM TIS Doc. C36100).
General Motors Technical Information System (TIS): Docs C36100, C36140, C36170, C36200, SIB 17-NA-022
EPA Engine Certification Database (EPA-ENG-LT4)
SAE International: J1349 Engine Power Test Code
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.
Locate the engine code stamped on the rear face of the cylinder block near the transmission bellhousing (GM TIS C36200). The 8th VIN digit indicates engine family ('4' for LT4 series). Pre-2017 models have silver valve covers with "LT4" branding; post-2017 units use black valve covers with "LT4" branding. Critical differentiation from L86: LT4 uses supercharged design; L86 uses naturally aspirated. Service parts require production date verification - bypass valves for engines before 08/2017 are incompatible with later units due to redesign (GM SIB 17-NA-022).
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.
Analysis derived from GM technical bulletins (2015-2020) and NHTSA failure statistics (2017-2022). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CADILLAC LT4.
Comprehensive technical documentation and regulatory references
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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