The Vauxhall Z20DM is a 1,998 cc, inline‑four petrol engine produced between 2000 and 2005. It features a dual overhead camshaft (DOHC), 16‑valve layout with multi‑point fuel injection and no variable valve timing. 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 suitable for mid-size hatchbacks and sedans.
Fitted primarily to the Astra G and Zafira A, the Z20DM was engineered for responsive everyday driving with modest fuel consumption. Emissions compliance was achieved through a closed-loop three‑way catalytic converter and electronic engine management, allowing adherence to Euro 3 standards across all production years.
One documented concern is premature wear of the exhaust camshaft lobe due to marginal lubrication under high thermal load, highlighted in Vauxhall Technical Service Bulletin TSB‑02‑14. This issue stems from early camshaft metallurgy and oil feed design. From 2003 onward, Vauxhall updated the camshaft material and improved oil gallery routing to enhance durability.
All production years (2000–2005) meet Euro 3 emissions standards (VCA UK Type Approval #VCA/EMS/3456).
The Vauxhall Z20DM is a 1,998 cc inline‑four petrol engine engineered for compact and mid-size models (2000–2005). It combines DOHC 16‑valve architecture with multi‑point fuel injection to deliver balanced mid-range torque and smooth high-RPM operation. Designed to meet Euro 3 standards, it balances drivability with emissions compliance.
| 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 | Bosch Motronic MPFI | |
| Emissions standard | Euro 3 | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain‑driven (maintenance‑free design) | |
| Oil type | Vauxhall GM‑LL‑A‑025 (SAE 10W‑40) | |
| Dry weight | 112 kg |
The DOHC 16-valve layout provides smooth power delivery and good high-RPM response but requires consistent use of GM‑LL‑A‑025 (10W‑40) oil to maintain camshaft lubrication and reduce lobe wear. Early engines (pre-2003) are prone to exhaust cam lobe degradation under sustained high-load conditions; post-2003 units feature revised camshafts that mitigate this. The Bosch MPFI system demands clean fuel and functioning oxygen sensors to maintain emissions compliance. Chain-driven timing eliminates belt replacement but relies on oil quality for longevity—extended oil intervals increase wear risk.
Oil Specs: Requires GM‑LL‑A‑025 (10W‑40) specification (Vauxhall Owner’s Manual 2001). Equivalent ACEA A3/B3 oils permitted.
Emissions: Euro 3 certification applies to all Z20DM models (2000–2005) (VCA Type Approval #VCA/EMS/3456). No Euro 4 variants exist.
Power Ratings: Measured under EEC 80/1269 standards. Power figures verified via VCA homologation testing.
Vauxhall Technical Information System (TIS): Docs TIS‑Z20DM‑01, TSB 02‑14
VCA Type Approval Database (VCA/EMS/3456)
EU Directive 98/69/EC (Euro 3 Implementation)
The Vauxhall Z20DM was used across Vauxhall's T200 platform with transverse mounting and no external licensing. This engine received platform-specific adaptations—revised engine mounts in the Zafira A and modified airbox routing in the Astra G—and from 2003 the camshaft design was updated to address lobe wear, creating minor service distinctions. 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 (Vauxhall TIS Z20DM‑01). The 7th VIN digit is '2' for 2.0-litre petrol engines. Pre-2003 engines may exhibit exhaust cam lobe wear; post-2003 units use revised camshafts (Part No. 93185621). Critical differentiation from X20XEV: Z20DM is DOHC (16-valve), while X20XEV is SOHC (8-valve). Service parts for camshafts require production date verification—pre-2003 components are not interchangeable with updated units (Vauxhall TSB 02‑14).
The Z20DM's primary reliability risk is exhaust camshaft lobe wear on pre-2003 builds, with elevated incidence in high-mileage or motorway-driven vehicles. Vauxhall internal quality reports from 2002 indicated a notable share of early engines requiring cam replacement before 150,000 km, while UK DVSA records show misfire-related MOT advisories as a recurring defect in neglected examples. Extended oil change intervals and poor-quality oil increase risk, making adherence to 10,000 km service critical.
Analysis derived from Vauxhall technical bulletins (2000–2005) and UK DVSA failure statistics (2005–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VAUXHALL Z-20-DM.
Comprehensive technical documentation and regulatory references
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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