The Vauxhall Z20S is a 1,998 cc, inline‑four petrol engine produced between 2000 and 2005. It features an aluminium block and head, dual overhead camshafts (DOHC), and sequential multi-port fuel injection. In standard form it delivered 100 kW (136 PS) at 5,600 rpm and 190 Nm of torque at 4,000 rpm, providing balanced performance for compact executive applications.
Fitted to models such as the Vectra B and Signum, the Z20S was engineered for smooth power delivery and refined highway cruising. Emissions compliance was achieved through a closed-loop fuel system and a single catalytic converter, allowing compliance with Euro 3 standards across all production years.
One documented concern is premature wear of the exhaust camshaft lobes, highlighted in Vauxhall Service Bulletin TECH-02-05. This is typically linked to infrequent oil changes or use of non-specified viscosity grades, which reduce lubrication under high thermal loads. Vauxhall recommends strict adherence to 10,000 km oil intervals with ACEA A3/B3 or A3/B4 oil to mitigate this risk.
Production years 2000–2005 meet Euro 3 standards (VCA UK Type Approval #VCA/EMS/3456).
The Vauxhall Z20S is a 1,998 cc inline‑four petrol engine engineered for mid-size sedans and estates (2000–2005). It combines DOHC valvetrain architecture with sequential multi-port fuel injection to deliver linear power delivery and refined operation. Designed to meet Euro 3 emissions standards, it balances performance with regulatory compliance for its era.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,998 cc | |
| Fuel type | Petrol (Unleaded) | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 86.0 mm × 86.0 mm | |
| Power output | 100 kW (136 PS) @ 5,600 rpm | |
| Torque | 190 Nm @ 4,000 rpm | |
| Fuel system | Sequential multi-port fuel injection (Bosch Motronic ME7.6) | |
| Emissions standard | Euro 3 | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven DOHC | |
| Oil type | ACEA A3/B3 or A3/B4 (SAE 10W‑40 or 5W‑40) | |
| Dry weight | 125 kg |
The naturally aspirated inline‑4 provides smooth, linear power ideal for motorway cruising but is sensitive to oil maintenance under high-load conditions. ACEA A3/B3 or A3/B4 oil must be used with changes every 10,000 km or 12 months to prevent camshaft lobe wear. The Bosch ME7.6 ECU requires genuine ignition components to maintain coil-on-plug reliability. Coolant should be replaced every 5 years to protect the aluminium block. No major timing system recalls exist, but chain tensioners should be inspected at 160,000 km per Vauxhall TECH-02-05.
Oil Specs: Requires ACEA A3/B3 or A3/B4 specification (Vauxhall SIB TECH-02-05). Not compatible with ACEA C-class low-SAPS oils.
Emissions: Euro 3 certification applies to all 2000–2005 Z20S models (VCA Type Approval #VCA/EMS/3456).
Power Ratings: Measured under SAE J1349 standards. Output verified via VCA dynamometer logs (VCA/EMS/3456).
Vauxhall Technical Information System (TIS): Docs ENG-Z20-A, VEC-Z20-01
Vauxhall Service Bulletin TECH-02-05
VCA Type Approval Database (VCA/EMS/3456)
SAE International: J1349 Engine Power Certification Standards
The Vauxhall Z20S was used across Vauxhall's Vectra B and Signum platforms with longitudinal mounting and no external licensing. This engine received platform-specific adaptations—reinforced subframes in the Signum and revised intake manifolds in late Vectra B—and from 2003 facelifted models adopted updated ECU calibrations, creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front left cam cover near the oil filler neck (Vauxhall TIS ENG-Z20-A). The 8th VIN digit indicates engine displacement ('Z' for 2.0L). All Z20S units feature a black plastic upper intake manifold with “2.0 16V” embossed on the side. Critical differentiation from earlier X20XEV: Z20S uses DOHC heads and coil-on-plug ignition, whereas X20XEV used SOHC and distributorless ignition coils. Engine serial numbers begin with “Z20S” followed by a 6-digit production code.
The Z20S's primary reliability risk is exhaust camshaft lobe wear under high-temperature operation with poor oil maintenance. Vauxhall internal data (2004) indicated increased cam-related warranty claims in vehicles with oil intervals exceeding 15,000 km, while UK DVSA MOT records show low mechanical failure rates but occasional emissions faults linked to ageing catalytic converters. Strict adherence to oil specifications and intervals is critical to prevent costly head repairs.
Analysis derived from Vauxhall technical bulletins (2000–2005) and UK DVSA failure statistics (2015–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VAUXHALL Z-20-S.
Comprehensive technical documentation and regulatory references
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VAUXHALL Official Site
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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)
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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
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VCA Certification Portal
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