The Citroën 170A (engine code XN1T) is a 1,997 cc, inline — four turbo — diesel engine developed in partnership with Ford and produced between 2004 and 2014. It features common rail direct injection, a variable geometry turbocharger (VGT), and DOHC valvetrain. In standard tune it delivered 80 kW (109 PS), with peak torque of 270 Nm, providing strong low — end pull ideal for urban and commercial use.
Fitted to models such as the Citroën C5, C8, and Relay van, the 170A was engineer…
Production years 2004–2009 meet Euro 4 standards; 2009–2014 models comply with Euro 5 depending on market (VCA UK Type Approval #VCA/EMS/5678).
The Citroën 170A (XN1T) is a 1,997 cc inline-four turbo-diesel engineered for mid-size and commercial vehicles (2004–2014). It combines common-rail direct injection with a variable geometry turbocharger to deliver responsive low-RPM torque and efficient highway cruising. Designed to meet Euro 4 and Euro 5 standards, it balances real-world economy with payload capability.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,997 cc | |
Fuel type | Diesel | |
Configuration | Inline-4, DOHC, 16-valve | |
Aspiration | Turbocharged (VGT) | |
Bore × stroke | 85.0 mm × 88.0 mm | |
Power output | 80 kW (109 PS) @ 3,500 rpm | |
Torque | 270 Nm @ 1,750–2,500 rpm | |
Fuel system | Bosch CRS 2.0 common rail (up to 1,600 bar) | |
Emissions standard | Euro 4 (pre-2009); Euro 5 (2009–2014) | |
Compression ratio | 17.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | Garrett variable geometry turbo (VNT20) | |
Timing system | Timing belt (interval: 180,000 km or 10 years) | |
Oil type | Total Quartz INEO ECS 5W-30 (ACEA C3) | |
Dry weight | 178 kg |
The Citroën 170A (XN1T) was used across Citroën's C5/C8/Relay platforms with longitudinal mounting and shared under the PSA/Ford joint-engineering agreement. This engine received platform-specific adaptations-shorter intake manifolds in the Relay and revised EGR cooling in the C5-and from 2009 the Euro 5 update introduced SCR and AdBlue injection, creating interchange limits. Partnerships enabled Ford's 2.0L TDCi units to use identical core architecture. All adaptations are documented in OEM technical bulletins.
The 170A's primary reliability risk is high-pressure fuel pump degradation, with elevated incidence in vehicles with extended service intervals. Internal Citroën quality reports from 2010 noted a significant number of pre-2009 units requiring HPFP replacement before 150,000 km, while UK DVSA MOT data links EGR/DPF clogging to frequent short trips. Poor fuel quality and infrequent regeneration cycles increase particulate and soot loading, making regular highway driving and proper oil specification critical.
Analysis derived from Citroën technical bulletins (2004–2014) and UK DVSA failure statistics (2010–2020). Repair procedures should follow manufacturer guidelines.
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The 170A is generally robust when maintained properly, but early Euro 4 models (2004–2008) are prone to HPFP and EGR issues. Later Euro 5 versions (2009–2014) improved fuel system durability and added SCR for cleaner operation. Regular servicing, quality diesel, and use of correct oil (5W-30 ACEA C3) are essential for longevity beyond 200,000 km.
The most documented issues are high-pressure fuel pump failure, EGR and intake carbon buildup, DPF regeneration problems, and timing belt wear. These are confirmed in Citroën service bulletins and DVSA failure reports. Using proper oil and avoiding short trips helps mitigate DPF and EGR faults.
The 170A (XN1T) was used in the Citroën C5 (2004–2014), C8 (2004–2014), and Relay (2006–2014) as the 2.0 HDi 110. It was also shared with Ford under the PSA/Ford alliance, appearing in the Transit 2.0 TDCi 110 PS (2006–2013). All models require ACEA C3 oil and specific service schedules.
Yes, the 170A responds well to ECU remapping. Stage 1 tunes typically increase output to 100–110 kW (136–150 PS) and 350–400 Nm. However, the stock turbo and fuel system limit higher gains. Supporting mods like upgraded intercooling and exhaust improve reliability under tuning. Always ensure DPF and EGR functions are preserved for road legality.
In a Citroën C5 2.0 HDi, combined consumption is approximately 5.8 L/100km (49 mpg UK). Highway driving can achieve 4.8 L/100km (59 mpg), while city use may rise to 7.0 L/100km (40 mpg). Real-world economy depends on load and driving style, but 45–55 mpg (UK) is typical for well-maintained units on mixed routes.
Yes, the 170A is an interference engine. If the timing belt fails or jumps, pistons can collide with open valves, causing catastrophic internal damage. Adhering to the 180,000 km or 10-year replacement interval is critical. Any signs of belt wear or tensioner noise should be addressed immediately.
Citroën specifies Total Quartz INEO ECS 5W-30 (ACEA C3) or equivalent low-SAPS oil. This protects the DPF and turbo from ash buildup. Oil must be changed every 15,000–20,000 km or annually to maintain engine and emissions system health. Using non-compliant oil can lead to DPF blockage and ECU faults.
Comprehensive technical documentation and regulatory references
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