The CADILLAC Z 20 NET is a 1,998 cc, naturally aspirated inline-four petrol engine produced between 2005 and 2011. It features DOHC, 16-valve configuration with sequential fuel injection and variable valve timing. Rated at 110 kW (150 PS) and 196 Nm of torque, this engine was developed for balanced performance and refinement in compact and mid-size applications.
Fitted to select European-market Cadillacs and badge-engineered Opel/Vauxhall models, the Z 20 NET was engineered for responsive driving dynamics while maintaining fuel efficiency and smoothness. Emissions compliance was achieved through close-coupled three-way catalytic converters and secondary air injection system, meeting Euro 4 standards for its production run.
One documented reliability concern is premature intake manifold runner actuator failure, particularly in early production units before 2008. This issue, referenced in General Motors Europe Service Information Bulletin 08-03-01, is attributed to plastic gear degradation in the actuator motor. In 2008, GM revised the actuator design with reinforced gears, improving durability in later models.
Production years 2005–2011 meet Euro 4 emissions standards (VCA UK Type Approval #VCA/EMS/Z20NET).
The CADILLAC Z 20 NET is a 1,998 cc inline-four naturally aspirated petrol engine engineered for compact and mid-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 Euro 4 standards, it balances performance with everyday drivability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,998 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 86.0 mm × 86.0 mm | |
| Power output | 110 kW (150 PS) @ 6,000 rpm | |
| Torque | 196 Nm @ 4,400 rpm | |
| Fuel system | Sequential multi-port fuel injection | |
| Emissions standard | Euro 4 | |
| Compression ratio | 10.2:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Double-row roller chain (non-interference design) | |
| Oil type | GM dexos1 Gen 0 (SAE 5W-30) | |
| Dry weight | 135 kg |
The naturally aspirated inline-four delivers responsive performance ideal for everyday driving but requires adherence to 15,000 km oil change intervals to prevent bearing and chain wear. GM dexos1 Gen 0 (5W-30) oil is essential due to its shear stability and protection for the timing chain system. Extended high-RPM operation or insufficient warm-up increases stress on the intake actuators in pre-2008 engines. The ECU is robust but sensitive to fuel quality; always use premium unleaded (RON 95+). Post-2008 models feature revised actuators per GM SIB 08-03-01, significantly enhancing long-term reliability.
Oil Specs: Requires GM dexos1 Gen 0 specification (GM SIB 08-03-01). API SM/ILSAC GF-4 compatible oils acceptable.
Emissions: Euro 4 certification applies to all models (2005–2011) (VCA Type Approval #VCA/EMS/Z20NET).
Power Ratings: Measured under SAE J1349 standards. Output consistent across fuel qualities (GM TIS Doc. C38100).
General Motors Technical Information System (TIS): Docs C38100, C38140, C38200, SIB 08-03-01
VCA Type Approval Database (VCA/EMS/Z20NET)
SAE International: J1349 Engine Power Test Code
The CADILLAC Z 20 NET was used across Opel/Vauxhall platforms with transverse mounting and no direct Cadillac-branded applications. This engine received platform-specific adaptations-revised intake in the Astra H and shorter accessory drives in the Zafira B-and from 2011 the facelifted Astra J adopted the Z20XEP with direct injection, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front face of the cylinder block near the timing cover (GM TIS C38200). The 8th VIN digit indicates engine family ('N' for Z20NET series). Pre-2008 models have silver valve covers with "Z20NET" branding; post-2008 units use black valve covers with "Z20NET" branding. Critical differentiation from Z20XEP: Z20NET uses port injection; Z20XEP uses direct injection. Service parts require production date verification - intake actuators for engines before 08/2008 are incompatible with later units due to gear redesign (GM SIB 08-03-01).
The Z 20 NET's primary reliability risk is intake manifold runner actuator failure in early builds, with elevated incidence in high-mileage vehicles. Internal GM Europe quality reports from 2008 noted a significant share of pre-2008 engines requiring actuator replacement before 120,000 km, while UK DVSA 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 UK DVSA failure statistics (2008-2015). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CADILLAC Z20NET.
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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