The Vauxhall D 14 NEH is a 1,399 cc, inline‑four turbocharged petrol engine produced between 2015 and 2020. It features direct fuel injection, dual overhead camshafts (DOHC), and variable valve timing. In standard form it delivers 103 kW (140 PS) and 200 Nm of torque, with strong mid-range response for everyday drivability.
Fitted to models such as the Astra K and Mokka X—including the Astra 1.4T 140 and Mokka X 1.4T—the D 14 NEH was engineered for responsive urban performance and efficient motorway cruising. Emissions compliance was achieved through a close-coupled three-way catalytic converter and exhaust gas recirculation (EGR), meeting Euro 6 standards across all production years.
One documented concern is excessive carbon buildup on intake valves due to the portless direct injection design, highlighted in Vauxhall Service Bulletin TIS‑14NEH‑09. This can lead to rough idle and reduced efficiency over time. From 2018, minor ECU calibrations were introduced to mitigate valve coking, though mechanical cleaning remains the primary remedy.
All production years 2015–2020 meet Euro 6 emissions standards (VCA UK Type Approval #VCA/EMS/5678).
The Vauxhall D 14 NEH is a 1,399 cc inline‑four turbocharged petrol engineered for compact hatchbacks and SUVs (2015–2020). It combines gasoline direct injection with a single twin-scroll turbocharger to deliver responsive low-end torque and smooth power delivery. Designed to meet Euro 6 standards, it balances performance with urban efficiency.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,399 cc | |
| Fuel type | Petrol (Unleaded) | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Turbocharged (twin‑scroll) | |
| Bore × stroke | 72.5 mm × 84.5 mm | |
| Power output | 103 kW (140 PS) | |
| Torque | 200 Nm @ 1,850–4,000 rpm | |
| Fuel system | Bosch HDEV5 direct injection (up to 200 bar) | |
| Emissions standard | Euro 6 | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Single twin‑scroll turbo (Honeywell) | |
| Timing system | Chain (front‑mounted; low‑wear design) | |
| Oil type | GM dexos2 (SAE 5W‑30) | |
| Dry weight | 125 kg |
The twin-scroll turbo provides immediate throttle response but requires adherence to 15,000 km oil change intervals using GM dexos2 (5W-30) to protect turbo bearings and timing chain. Direct injection causes carbon buildup on intake valves due to lack of fuel washing; periodic walnut blasting or intake cleaning is recommended after 80,000 km. Use of E10 petrol is permitted per Vauxhall guidance. The front-mounted timing chain is robust but sensitive to oil degradation—extended intervals risk tensioner wear. EGR system must remain functional to maintain Euro 6 compliance and prevent DPF-like particulate filter loading in GPF-equipped variants.
Oil Specs: Requires GM dexos2 (5W-30) specification (Vauxhall Owner’s Manual 2016). Meets ACEA C3 but with GM-specific additives.
Emissions: Euro 6 certification applies to all 2015–2020 models (VCA Type Approval #VCA/EMS/5678). Includes GPF on post-2018 builds.
Power Ratings: Measured under SAE J1349 standards. Output consistent across all markets (Vauxhall TIS Doc. T14NEH‑C).
Vauxhall Technical Information System (TIS): Docs T14NEH‑A, T14NEH‑B, SIB TIS‑14NEH‑09
VCA Type Approval Database (VCA/EMS/5678)
SAE International: J1349 Engine Power Certification Standards
The Vauxhall D 14 NEH was used across Vauxhall's Astra K and Mokka X platforms with transverse mounting and no external licensing. This engine received platform-specific adaptations—revised engine mounts in the Mokka X for NVH control and unique exhaust manifolds in the Astra Sports Tourer—and from 2018 the addition of a gasoline particulate filter (GPF) for WLTP compliance, creating minor ECU and exhaust differences. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front timing cover near the oil filler neck (Vauxhall TIS T14NEH‑A). The 7th VIN digit is 'D' for 1.4L turbo petrol engines. Pre-2018 units lack a gasoline particulate filter (GPF) and use ECU part number 13578901; post-2018 GPF-equipped variants use ECU 13578915 with updated lambda control. Critical differentiation from B 14 NET: D 14 NEH has a twin-scroll turbo and higher torque output. Service parts for exhaust and ECU are not interchangeable across GPF boundaries (Vauxhall SIB TIS‑14NEH‑12).
The D 14 NEH's primary reliability risk is intake valve carbon buildup due to its direct-injection design, with elevated incidence in short-trip urban use. Vauxhall internal data (2019) indicated over 30% of engines required cleaning by 100,000 km, while UK DVSA MOT records show increased emissions-related failures in high-mileage examples. Frequent cold starts and low-load operation accelerate deposit formation, making periodic intake maintenance critical.
Analysis derived from Vauxhall technical bulletins (2016–2020) and UK DVSA failure statistics (2018–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VAUXHALL D-14-NEH.
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
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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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