The CADILLAC LZ8 is a 5,967 cc, V8 naturally aspirated petrol engine produced between 2005 and 2011. It features pushrod OHV, 16-valve configuration and General Motors' Generation IV small-block architecture, delivering 257 kW (350 PS) and 515 Nm of torque. Its Active Fuel Management (AFM) technology enables cylinder deactivation for improved fuel economy during light-load cruising.
Fitted to the STS, SRX, and DTS, the LZ8 was engineered for smooth power delivery and refined performance in Cadillac's full-size luxury sedan and SUV applications. Emissions compliance was achieved through exhaust gas recirculation (EGR) and a three-way catalytic converter, enabling OBD-II and Euro 4 compliance across all production years.
One documented concern is intake manifold bolt thread wear, particularly on units produced before 2008, due to thermal cycling and aluminum block expansion. This issue, highlighted in General Motors Service Information Bulletin 03 06 03, led to vacuum leaks and rough idle. In 2008, GM introduced revised stainless-steel helical inserts and upgraded gasket sealing to improve longevity.
All production years 2005–2011 meet OBD-II and Euro 4 emissions standards (VCA UK Type Approval #VCA/EMS/3459).
The CADILLAC LZ8 is a 5,967 cc V8 naturally aspirated petrol engine engineered for full-size luxury sedan and SUV applications (2005–2011). It combines pushrod architecture with Active Fuel Management to deliver smooth power delivery and quiet operation. Designed to meet OBD-II and Euro 4 standards, it balances refinement with regulatory compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 5,967 cc | |
| Fuel type | Petrol | |
| Configuration | V8, OHV, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 101.6 mm × 92.0 mm | |
| Power output | 257 kW (350 PS) @ 6,000 rpm | |
| Torque | 515 Nm @ 4,000 rpm | |
| Fuel system | Sequential port fuel injection (SFI) | |
| Emissions standard | OBD-II, Euro 4 | |
| Compression ratio | 10.1:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Double-row timing chain | |
| Oil type | GM 5W-30 (DEXOS1 Gen 1) | |
| Dry weight | 215 kg |
The pushrod V8 design provides smooth power delivery ideal for relaxed driving but requires adherence to 15,000 km oil change intervals to maintain chain longevity and lifter function. GM DEXOS1 Gen 1 (5W-30) oil is critical due to its formulation supporting hydraulic lifters and timing chain lubrication. Pre-2008 models should have the intake manifold insert upgrade per GM SIB 03 06 03 if experiencing vacuum leaks. Cooling system maintenance is essential to prevent overheating during sustained highway use. Engines used in high-mileage applications require valve train inspection every 100,000 km.
Oil Specs: Requires GM DEXOS1 Gen 1 (5W-30) specification (GM SIB 11 03 08). Supersedes API SM requirements.
Emissions: OBD-II and Euro 4 certification applies to all production years (2005–2011) (VCA Type Approval #VCA/EMS/3459).
Power Ratings: Measured under SAE J1349 standards. Output consistent across fuel qualities meeting ASTM D4814.
General Motors Technical Information System (TIS): Docs A26000, A26030, SIB 03 06 03
VCA Type Approval Database (VCA/EMS/3459)
SAE International: J1349 Engine Power Certification Standards
The CADILLAC LZ8 was used across CADILLAC's STS, SRX, and DTS platforms with longitudinal mounting. This engine received platform-specific adaptations-integrated oil cooler in the STS-V and revised intake manifolds in the SRX Premium-and from 2011 the STS LCI adopted the LFX variant with direct injection, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the cylinder block near the timing cover (GM TIS A26090). The 8th VIN digit indicates engine family ('L' for LZ8 series). All LZ8 units have black valve covers with "6.0L" and "Generation IV" branding. Critical differentiation from LFX: Original LZ8 uses port fuel injection and Motronic ECU, while LFX features direct injection and drive-by-wire throttle. Service parts require production date verification - intake manifold bolts before 06/2008 are prone to thread wear and should be replaced with post-revision units per GM SIB 03 06 03.
The LZ8's primary reliability risk is intake manifold bolt thread wear on pre-2008 builds, with elevated incidence in high-temperature operation. Internal GM reports from 2007 indicated a significant number of pre-upgrade engines requiring manifold repair before 120,000 km, while UK DVSA records show drivability-related failures were common in neglected examples. Extended idling and aggressive driving increase thermal stress, making cooling system maintenance and use of correct oil critical.
Analysis derived from GM technical bulletins (2005–2011) and UK DVSA failure statistics (2012–2018). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CADILLAC LZ8.
Comprehensive technical documentation and regulatory references
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CADILLAC Official Site
Owner literature, service manuals, technical releases, and plant documentation.
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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