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…
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 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.
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.
The most common questions about engine codes, what they mean, how to find them and how this database works
The LZ8 offers smooth performance and solid engineering, but pre-2008 models with original intake manifold bolts are prone to thread wear. Later revisions with stainless-steel inserts significantly improve durability. Regular oil changes, use of correct oil (5W-30 GM DEXOS1), and prompt attention to idle quality are essential for reliability.
Key issues include intake manifold bolt thread wear (especially pre-2008), cooling system failures (thermostat, water pump), camshaft/lifter wear, and oil leaks from valve cover and rear main seal. These are documented in GM service bulletins and require OEM-specified parts for proper repair.
The LZ8 was used in the STS (2005–2011), SRX (2007–2011), and DTS (2006–2011). It was replaced by the LFX in 2011 with direct injection and updated engine management. No cross-manufacturer applications are documented for this variant.
Yes, though naturally aspirated. Stage 1 tuning includes ECU remap, high-flow intake, and performance exhaust, gaining ~15–25 kW. Cylinder head porting and camshaft upgrades offer further gains. Reliability depends on maintaining cooling and oil systems, especially with increased thermal load.
In an STS, combined consumption is ~14.5 L/100km (19 mpg UK). City driving may see 16–18 L/100km (18–16 mpg), while highway cruising can achieve ~11.0 L/100km (26 mpg). Real-world figures depend on driving style and vehicle condition.
No. The LZ8 series is a non-interference engine. If the timing chain fails or jumps, pistons will not contact open valves, preventing catastrophic internal damage. However, chain maintenance is still recommended to ensure proper valve timing and prevent secondary damage.
GM specifies 5W-30 synthetic oil meeting DEXOS1 Gen 1 spec. Change intervals should not exceed 15,000 km. Proper oil ensures adequate protection for camshafts, lifters, and the timing chain, especially under sustained high-RPM use.
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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