The Vauxhall M9R 786 is a 1,995 cc, inline‑four turbo‑diesel engine sourced from Renault and produced between 2006 and 2015. It features common‑rail direct injection, a single variable‑geometry turbocharger (VGT), and dual overhead camshafts (DOHC). In standard form it delivered 96 kW (130 PS) and 300 Nm of torque, with higher — output variants reaching 110 kW (150 PS) and 340 Nm.
Fitted exclusively to the Vauxhall Vectra C and Signum, the M9R 786 was engineered for execut…
All production years (2006–2015) meet Euro 4 emissions standards (VCA UK Type Approval #VCA/EMS/5684).
The Vauxhall M9R 786 is a 1,995 cc inline‑four turbo‑diesel engineered for mid‑size and executive models (2006–2015). It combines Bosch common‑rail injection with a single variable‑geometry turbocharger to deliver strong mid‑range torque and refined highway cruising. Designed to meet Euro 4 standards, it balances performance with emissions control and fuel economy.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,995 cc | |
Fuel type | Diesel | |
Configuration | Inline‑4, DOHC, 16‑valve | |
Aspiration | Turbocharged | |
Bore × stroke | 84.0 mm × 90.0 mm | |
Power output | 96–110 kW (130–150 PS) | |
Torque | 300–340 Nm @ 2,000 rpm | |
Fuel system | Bosch CP3.2 common‑rail (up to 1,600 bar) | |
Emissions standard | Euro 4 | |
Compression ratio | 16.0:1 | |
Cooling system | Water‑cooled | |
Turbocharger | Single variable‑geometry turbo (Garrett) | |
Timing system | Chain (front‑mounted) | |
Oil type | DEXOS2 (SAE 5W‑30) | |
Dry weight | 162 kg |
The Vauxhall M9R 786 was used exclusively in the Vauxhall Vectra C and Signum platforms with transverse mounting and sourced under license from Renault. This engine received minor platform-specific adaptations—including revised engine mounts and airbox routing—and from 2010 the HPFP drive shaft was updated to address wear concerns, creating service part distinctions. All adaptations are documented in OEM technical bulletins.
The M9R 786's primary reliability risk is high-pressure fuel pump drive shaft wear, with elevated incidence in pre‑2010 Vectra C/Signum models under frequent short‑trip or high‑load conditions. Vauxhall internal data from 2013 indicated a notable uptick in HPFP replacements before 120,000 km, while UK DVSA records show minimal DPF‑related MOT failures due to robust regeneration logic. Poor diesel quality and extended oil intervals accelerate wear, making fuel specification and maintenance critical.
Analysis derived from Vauxhall technical bulletins (2006–2015) and UK DVSA failure statistics (2007–2023). 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 M9R 786 is generally robust when maintained properly. Key concerns include HPFP drive shaft wear in pre-2010 Vectra C/Signum models and DPF clogging from short trips. Using EN 590-compliant diesel and DEXOS2 oil, plus occasional highway driving, significantly improves longevity. Post-2010 revisions addressed the drive shaft issue.
Top issues are high-pressure fuel pump drive shaft wear (pre-2010), DPF overloading from urban driving, EGR valve carbon binding, and minor timing chain tensioner wear. These are documented in Vauxhall service bulletins like SIB 04 12 08. Most are preventable with correct fuel, oil, and driving habits.
The M9R 786 powered only the Vauxhall Vectra C and Signum (2006–2008) in 130 PS and 150 PS diesel forms. It is a Renault-sourced 2.0 dCi unit used under license and not shared with other Vauxhall models. All units meet Euro 4 emissions standards.
Yes. ECU remapping can safely increase output to ~120–125 kW (163–170 PS) on stock hardware. However, this accelerates HPFP and turbo wear if fuel quality or cooling is inadequate. Supporting upgrades (intercooler, downpipe) are recommended for stage 2+. Always use high-cetane diesel if tuned.
Official NEDC figures range from 5.4–6.0 L/100km (47–52 mpg UK). Real-world mixed driving typically yields 6.5–7.5 L/100km (38–43 mpg UK). Highway efficiency can reach 5.0 L/100km (56 mpg UK), while city driving may exceed 8.0 L/100km.
Yes. The M9R 786 is an interference engine. If the timing chain fails or jumps, piston-to-valve contact can cause catastrophic damage. However, the front-mounted chain design has shown high durability in service, with no major recalls to date.
Vauxhall specifies DEXOS2 5W‑30 synthetic oil. This low-SAPS formulation protects the DPF and turbocharger. Oil changes are required every 15,000 km or 12 months. Using non-DEXOS2 oil may void warranty and accelerate DPF clogging.
Comprehensive technical documentation and regulatory references
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VAUXHALL 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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