The CADILLAC LY7 is a 3,564 cc, naturally aspirated V6 petrol engine produced between 2005 and 2011. It features DOHC, 24 — valve configuration with variable valve timing and sequential fuel injection. Rated at 190 kW (258 PS) and 350 Nm of torque, this engine was developed for balanced performance and refinement in Cadillac's mid — size and full — size sedan lineup.
Fitted to the STS, DTS, and CTS, the LY7 was engineered for responsive driving dynamics while maintaining smoo…
Cadillac
Production years 2005–2011 meet U.S. EPA Tier 2 Bin 5 and LEV III ULEV-70 standards (EPA Certification #EPA-ENG-LY7).
The CADILLAC LY7 is a 3,564 cc V6 naturally aspirated petrol engine engineered for full-size sedans (2005–2011). It combines DOHC architecture with sequential fuel injection and variable valve timing to deliver responsive throttle response and smooth power delivery. Designed to meet U.S. emissions standards, it balances performance with everyday drivability.
| Parameter | Value | Source |
|---|---|---|
Displacement | 3,564 cc | |
Fuel type | Petrol | |
Configuration | V6, DOHC, 24-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 94.0 mm × 85.6 mm | |
Power output | 190 kW (258 PS) @ 6,000 rpm | |
Torque | 350 Nm @ 4,400 rpm | |
Fuel system | Sequential multi-port fuel injection | |
Emissions standard | U.S. EPA Tier 2 Bin 5 / LEV III ULEV-70 | |
Compression ratio | 10.4:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Double-row roller chain (non-interference design) | |
Oil type | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 185 kg |
The CADILLAC LY7 was used across CADILLAC's GM Sigma/Omega platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-reinforced mounts in the DTS and revised intake in the STS-and from 2011 the facelifted CTS adopted the LFX V6, creating interchange limits. All adaptations are documented in OEM technical bulletins.
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The LY7's primary reliability risk is intake manifold runner actuator failure in early builds, with elevated incidence in high-mileage vehicles. Internal GM quality reports from 2008 noted a significant share of pre-2008 engines requiring actuator 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 actuator stress, making oil quality and operational procedure critical.
Analysis derived from GM technical bulletins (2005-2011) and NHTSA failure statistics (2008-2015). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The LY7 is generally robust, but early models (2005–2008) are prone to intake actuator failure. Later revisions (post-2008) with improved actuator design significantly enhance longevity. Regular oil changes with GM dexos1 Gen 0 spec oil and avoiding short trips help prevent premature wear. Well-maintained engines often exceed 180,000 km.
Key issues include intake manifold runner actuator failure (pre-2008), coolant leaks from plastic thermostat housing, valve cover oil leaks, and timing chain tensioner wear. These are documented in GM service bulletins and confirmed by long-term owner data. The actuator issue is particularly critical due to thermal cycling in early units.
The LY7 was used in the STS (2005-2011), DTS (2006-2011), and CTS (2005-2011). It replaced the L36-based prototypes and was later superseded by the LFX V6. All applications meet U.S. EPA Tier 2 Bin 5 emissions standards.
Aftermarket ECU tuning is common on the LY7 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 an STS, combined consumption is ~11.2 L/100km (~25 mpg US). Highway driving yields ~9.0 L/100km (~31 mpg US), while city use can reach 14.0 L/100km (~17 mpg US). Real-world figures depend on driving style, but the engine is efficient for a 3.6L naturally aspirated V6 of its era.
No. The LY7 uses a non-interference design. If the timing chain fails, pistons will not contact valves, preventing 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 0 spec. Use high-quality synthetic oil and change every 15,000 km or annually. Proper oil selection is critical to protect the timing system and actuators, especially in pre-2008 engines. Avoid low-detergent or non-synthetic oils.
Comprehensive technical documentation and regulatory references
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Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
EUR-Lex
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
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
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.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
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