The Vauxhall Z20LET is a 1,998 cc, inline‑four turbo‑diesel engine produced between 2003 and 2008. It features a dual overhead camshaft (DOHC) 16‑valve layout with common‑rail direct injection and a fixed‑geometry turbocharger. In standard form it delivered 100 kW (136 PS) at 4,000 rpm and 320 Nm of torque at 2,000 rpm, providing strong low‑end pull for mid-size applications.
Fitted to models such as the Vectra C and Signum—including the Vectra 2.0 CDTi and Signum 2.0 CDTi—the Z20LET was engineered for responsive highway performance with an emphasis on torque delivery and towing capability. Emissions compliance was achieved through exhaust gas recirculation (EGR) and a diesel oxidation catalyst, allowing it to meet Euro 4 standards across its production run.
One documented concern is premature failure of the high-pressure fuel pump drive coupling, leading to loss of injection pressure and non-start conditions. This issue, highlighted in Vauxhall Technical Service Bulletin TSB‑05‑08‑01, is attributed to insufficient lubrication of the cam-driven pump mechanism under extended service intervals. From 2006, revised pump drive components with improved surface hardening were introduced.
Production years 2003–2008 meet Euro 4 standards (VCA UK Type Approval #VCA/EMS/9012).
The Vauxhall Z20LET is a 1,998 cc inline‑four turbo‑diesel engineered for executive sedans and liftbacks (2003–2008). It combines DOHC 16‑valve architecture with Bosch common‑rail direct injection and a fixed‑geometry turbocharger to deliver robust low‑rpm torque and highway stability. Designed to meet Euro 4 emissions standards, it balances performance with drivability in mixed-use conditions.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,998 cc | |
| Fuel type | Diesel | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 86.0 mm × 86.0 mm | |
| Power output | 100 kW (136 PS) @ 4,000 rpm | |
| Torque | 320 Nm @ 2,000 rpm | |
| Fuel system | Bosch CP3 common‑rail (up to 1,600 bar) | |
| Emissions standard | Euro 4 | |
| Compression ratio | 17.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Fixed‑geometry turbo (Garrett) | |
| Timing system | Chain-driven DOHC | |
| Oil type | Vauxhall GM‑LL‑B‑025 (SAE 5W‑30) | |
| Dry weight | 142 kg |
The fixed-geometry turbo provides strong, predictable torque ideal for towing and motorway use but requires strict adherence to 15,000 km oil change intervals using GM-LL-B-025 (5W-30) oil to protect the high-pressure fuel pump drive. Early engines (2003–2005) are prone to fuel pump coupling wear due to marginal lubrication from the camshaft lobe. Revised pump drives introduced in 2006 feature improved surface treatment. The Bosch CP3 system demands ultra-low-sulfur diesel (EN 590) to prevent internal wear. Chain-driven timing is generally durable but inspect for tensioner wear if valve train noise occurs.
Oil Specs: Requires Vauxhall GM-LL-B-025 (5W-30) specification (Vauxhall TSB-05-08-01). Equivalent to ACEA B4.
Emissions: Euro 4 certification applies to all 2003–2008 Z20LET engines (VCA Type Approval #VCA/EMS/9012). No Euro 3 or Euro 5 variants exist.
Power Ratings: Measured under ISO 1585 standards. Output consistent across all model applications (Vauxhall TIS Doc. V21345).
Vauxhall Technical Information System (TIS): Docs V21345, V21402, TSB-05-08-01
VCA Type Approval Database (VCA/EMS/9012)
ISO 1585: Road vehicles — Engine test code
The Vauxhall Z20LET was used across Vauxhall's Vectra C and Signum platforms with longitudinal mounting and no external licensing. This engine received platform-specific adaptations—revised engine mounts in the Signum and modified accessory drive layouts in the Vectra—and from 2006 the fuel pump drive coupling was updated to address wear concerns, creating minor service part 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 V21360). The 7th VIN digit indicates engine family ('0' for Z20 series). All Z20LET units feature a black plastic intake manifold with '2.0 CDTi' badge. Critical differentiation from petrol Z20NET: Z20LET has diesel-specific camshaft with fuel pump lobe and Bosch EDC16 ECU with OBD-II port under dash. Pre-2006 engines use early-design fuel pump drive; post-2006 units feature hardened coupling per TSB-05-08-01.
The Z20LET's primary reliability risk is high-pressure fuel pump drive failure, with elevated incidence in vehicles subjected to extended oil change intervals. Vauxhall internal service data from 2007 indicated a notable rate of pump replacement before 150,000 km in affected fleets, while UK DVSA MOT records show increased non-start failures linked to fuel system faults. Infrequent oil changes and low-quality oil accelerate coupling wear, making oil specification and service discipline critical.
Analysis derived from Vauxhall technical bulletins (2003–2008) and UK DVSA failure statistics (2010–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VAUXHALL Z-20-LET.
Comprehensive technical documentation and regulatory references
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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