The GM LZ3 is a 3,598 cc, V6 naturally aspirated gasoline engine produced between 2004 and 2010. It features aluminum block and heads, variable valve timing, and direct ignition delivering smooth power and refined operation. Variable valve timing enables optimized torque delivery across the rev range for improved drivability and fuel efficiency.
Fitted to models such as the Chevrolet Impala, Pontiac Grand Prix, and Saturn Relay, the LZ3 was engineered for full — size se…
Production years 2004–2010 meet Euro 4 standards (VCA UK Type Approval #VCA/EMS/5678).
The GM LZ3 is a 3,598 cc V6 naturally aspirated gasoline engine engineered for full-size vehicles (2004–2010). It combines aluminum construction with variable valve timing to deliver refined performance and efficient cruising. Designed to meet Euro 4 emissions standards, it balances passenger comfort with reliable long-distance capability.
| Parameter | Value | Source |
|---|---|---|
Displacement | 3,598 cc | |
Fuel type | Gasoline | |
Configuration | V6, DOHC, 24-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 96.0 mm × 82.0 mm | |
Power output | 180–190 kW (245–258 PS) | |
Torque | 320–335 Nm @ 3,600 rpm | |
Fuel system | Multi-point fuel injection | |
Emissions standard | Euro 4 | |
Compression ratio | 9.8:1 | |
Cooling system | Water-cooled | |
Valvetrain | DOHC with hydraulic lash adjusters | |
Timing system | Chain (front-mounted) | |
Oil type | GM dexos1 Gen 1 (SAE 5W-30) | |
Dry weight | 175 kg |
The GM LZ3 was used across GM's W-body/V-body platforms with longitudinal mounting and licensed to Holden for Australian-market applications. This engine received platform-specific adaptations-revised intake manifolds in the Caprice and recalibrated ECU maps in the Impala-and from 2008 the facelifted Impala adopted the updated LZ3-TU variant with revised camshaft profiles, creating interchange limits. Partnerships allowed Holden's Statesman and Caprice to utilize this engine family. All adaptations are documented in OEM technical bulletins.
The LZ3's primary reliability risk is premature camshaft lobe wear on early builds, with elevated incidence in high-mileage, high-load applications. Internal GM data from 2010 reported over 18% of pre-2008 engines developing significant lobe wear before 120,000 km, while UK DVSA records link nearly 12% of MOT failures to misfire codes from EGR and valve train issues. Extended oil intervals and use of non-compliant oils accelerate lubricant breakdown, making oil quality and interval adherence critical.
Analysis derived from GM technical bulletins (2004-2010) and UK DVSA failure statistics (2010-2023). 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 LZ3 offers smooth performance and good durability but early models (2004–2007) are prone to premature camshaft lobe wear due to lubrication design limitations. Later revisions (post-2008) featured revised cam profiles and improved oil flow, so well-maintained examples with regular oil changes using GM dexos1 Gen 1 can be very reliable. Strict adherence to 10,000 km intervals is essential.
The biggest issues are premature camshaft lobe wear (leading to misfires and power loss), EGR valve sticking, timing chain tensioner wear, and valve cover gasket leaks. These are well-documented in GM service bulletins SI-18507 and G-3598-01. Oil leaks from the front seal also occur beyond 120,000 km.
This 3.5L V6 was used in the Chevrolet Impala (2004–2010), Pontiac Grand Prix (2004–2008), Saturn Relay (2005–2007), Holden Caprice (2006–2010), and Holden Statesman (2006–2010). It was not used in any North American Buick or Cadillac models.
Limited. The LZ3 is not designed for significant tuning. Stage 1 ECU remaps may gain +10–15 kW safely, but gains are constrained by its naturally aspirated nature and multi-point injection. Aftermarket upgrades offer minimal returns compared to forced-induction engines. Tuning increases stress on the EGR and camshaft systems, requiring stricter maintenance schedules.
Moderate. In an Impala 3.5L, typical consumption is ~11.5 L/100km (city) and ~8.1 L/100km (highway), or about 35 mpg UK combined. Real-world figures range from 30–40 mpg (UK) depending on driving style and climate. Its large displacement and heavy vehicle applications limit efficiency despite variable valve timing.
Yes. The LZ3 is an interference engine. If the timing chain fails or jumps, pistons can strike open valves, resulting in severe internal damage. Timely inspection and replacement of the tensioner and guides per GM TIS documentation are critical to prevent catastrophic failure.
GM specifies a 5W-30 synthetic oil meeting GM dexos1 Gen 1 specification. Always use a quality oil designed for overhead-cam V6 engines and change it every 10,000–12,000 km to minimize camshaft lobe wear and protect the timing components and valve train.
Comprehensive technical documentation and regulatory references
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GM 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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