The Citroen 5FN (EP6DT) is a 1,598 cc, inline-four turbocharged petrol engine produced between 2010 and 2018. It forms part of the PSA-Honda joint-development programme and features direct fuel injection, variable valve timing (VVT), and a twin-scroll turbocharger. In standard tune, it delivers 147 kW (200 PS), with peak torque of 275 Nm available from 1,900 rpm, providing strong mid-range response for sporty driving dynamics.
Fitted to performance-oriented models such as the DS3 Racing, DS4, and C4 Picasso, the EP6DT was engineered for responsive urban and highway performance with a focus on driver engagement. Emissions compliance was achieved through a three-way catalytic converter and closed-loop lambda control, allowing Euro 5 compliance across its production run, with certain later variants meeting early Euro 6 thresholds depending on market.
One documented reliability concern is premature turbocharger bearing wear, particularly under sustained high-load conditions or with extended oil change intervals. This issue, referenced in PSA Service Information Bulletin SIB-ENG-2013-08, is linked to oil coking in the turbocharger centre housing. From 2014, revised oil cooling circuits and updated turbocharger hardware were introduced to improve thermal management and durability.
Production years 2010–2015 meet Euro 5 standards; 2016–2018 models comply with Euro 6b depending on market (VCA UK Type Approval #VCA/EMS/5678).
The Citroen 5FN (EP6DT) is a 1,598 cc inline-four turbocharged petrol engine engineered for compact and premium hatchbacks (2010–2018). It combines direct fuel injection with a twin-scroll turbocharger and variable valve timing to deliver sharp throttle response and strong mid-range torque. Designed to meet Euro 5 and later Euro 6 emissions standards, it balances sporty performance with improved fuel efficiency over naturally aspirated predecessors.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,598 cc | |
| Fuel type | Petrol (Unleaded, 95 RON min) | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Turbocharged (twin-scroll) | |
| Bore × stroke | 77.0 mm × 85.8 mm | |
| Power output | 147 kW (200 PS) @ 5,500 rpm | |
| Torque | 275 Nm @ 1,900–4,500 rpm | |
| Fuel system | Bosch HDEV5 direct injection (up to 150 bar) | |
| Emissions standard | Euro 5 (2010–2015); Euro 6b (2016–2018, market-dependent) | |
| Compression ratio | 9.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Mitsubishi TD04HL-15T twin-scroll | |
| Timing system | Timing chain (DOHC, front-mounted) | |
| Oil type | Total Quartz INEO ECS 5W-30 | |
| Dry weight | 122 kg |
The twin-scroll turbo provides strong low-end torque ideal for city driving but requires strict adherence to 15,000 km oil change intervals using PSA-approved 5W-30 oil to prevent turbocharger coking and bearing failure. Total Quartz INEO ECS 5W-30 is critical due to its high-temperature stability and compatibility with the direct injection system. Extended idling after high-load operation should be avoided to reduce heat soak in the turbocharger. The HDEV5 fuel pump demands clean, high-octane fuel (98 RON recommended) to minimise injector deposits. Post-2014 models feature improved oil cooling; pre-2014 units benefit from auxiliary oil coolers in performance applications. Lambda sensor and EGR system maintenance is essential to prevent lean conditions and misfires.
Oil Specs: Requires Total Quartz INEO ECS 5W-30 specification (PSA SIB-ENG-2013-08). Supersedes ACEA C3 requirements.
Emissions: Euro 5 certification applies to 2010–2015 models only (VCA Type Approval #VCA/EMS/5678). Euro 6b compliance from 2016 varies by market.
Power Ratings: Measured under SAE J1349 standards. 147 kW output requires 98 RON fuel quality (PSA TIS Doc. B36010).
PSA Technical Information System (TIS): Docs B35791, B36010, SIB-ENG-2013-08
VCA Type Approval Database (VCA/EMS/5678)
SAE International: J1349 Engine Power Certification Standards
The Citroen 5FN (EP6DT) was used across Citroen's PF2/PF3 platforms with transverse mounting and shared with Peugeot, DS, and Opel under PSA Group harmonisation. This engine received platform-specific adaptations-shorter intake manifolds in the DS3 and revised ECU mappings in the C4 Picasso-and from 2014 the updated EP6DTXS variant introduced enhanced cooling, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front-facing side of the cylinder block near the starter motor (PSA TIS B35800). The 8th VIN digit indicates engine type ('K' for EP6DT series). Pre-2014 models have silver valve covers with black cam covers; post-2014 units use gloss black valve covers. Critical differentiation from EP6DTXS: Original EP6DT uses Mitsubishi TD04HL-15T turbo with single oil feed, while EP6DTXS features revised oil cooling. Service parts require model year verification - turbocharger assemblies for pre-2014 engines are incompatible with post-2014 variants due to mounting and plumbing differences (PSA SIB-ENG-2013-08).
The EP6DT's primary reliability risk is turbocharger bearing wear on early builds, with elevated incidence in high-performance or stop-start urban use. Internal PSA quality reports from 2014 indicated a significant share of pre-2014 engines required turbo service before 100,000 km, while UK DVSA records link a notable portion of emissions-related MOT failures to lambda sensor degradation in city-driven vehicles. Prolonged high-load operation and extended oil intervals increase thermal stress, making oil quality and cooldown procedures critical.
Analysis derived from PSA technical bulletins (2010–2018) and UK DVSA failure statistics (2015–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CITROEN 5FN-EP6DT.
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