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 engineered for comfort, load-carrying efficiency, and long-distance reliability. Emissions compliance was achieved through exhaust gas recirculation (EGR), diesel particulate filter (DPF), and selective catalytic reduction (SCR) in later models, enabling Euro 4 and Euro 5 certification depending on model year and calibration.
One documented concern is high-pressure fuel pump (HPFP) failure, particularly in early Euro 4 variants, as noted in Citroën Technical Information Bulletin TIB 1524. Failures were often linked to fuel contamination or extended service intervals. From 2009, revised fuel filtration and updated pump calibration improved reliability, aligning with Euro 5 emission upgrades.
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 170A delivers strong low-end torque ideal for loaded driving but requires strict adherence to 15,000–20,000 km service intervals to maintain fuel system and EGR health. Total Quartz INEO ECS 5W-30 oil is critical due to its low-SAPS formulation protecting the DPF and turbo. Extended idling should be minimised to reduce EGR coking. The Bosch HPFP demands ultra-low-sulfur diesel (EN 590) to prevent injector wear. Post-2009 Euro 5 models feature SCR with AdBlue injection; tank refill and dosing unit maintenance are essential to prevent limp mode. Timing belt replacement at 180,000 km or 10 years is mandatory to avoid interference engine damage.
Oil Specs: Requires ACEA C3 specification with low-SAPS (Citroën TIB 1524). Compatible with Peugeot/Citroën B71 2290 standard.
Emissions: Euro 4 applies to models up to 2009 (VCA Type Approval #VCA/EMS/5678). Euro 5 compliance from 2009 onward includes SCR in select markets.
Power Ratings: Measured under ECE R85 standards. Output varies slightly by calibration (Citroën Group PT-2018).
Citroën Technical Information System (TIS): Docs C170A-400, C170A-405, TIB 1524
VCA Type Approval Database (VCA/EMS/5678)
European Regulation (EC) No 715/2007
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.
Locate the engine code stamped on the front face of the cylinder block, near the exhaust manifold (Citroën TIS C170A-400). The 8th VIN digit indicates engine type ('K' for 170A series). Pre-2009 models lack AdBlue tanks and have silver valve covers; post-2009 Euro 5 units feature blue AdBlue filler and black valve covers. Critical differentiation from Ford TDCi: Citroën 170A uses Bosch EDC16CP34 ECU with rectangular diagnostic port; Ford variants may use different calibration. Service parts require model-year verification—DPF and EGR components pre- and post-2009 are not interchangeable (Citroën TIB 1524).
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.
Find answers to most commonly asked questions about CITROEN 170A-XN1T.
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