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…

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 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.
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.
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The EP6DT delivers strong performance and responsive driving dynamics, but early models (2010–2013) had reliability concerns, particularly turbocharger and injector issues. Later revisions (post-2014) improved thermal management and component durability, so well-maintained examples can be robust. Regular servicing and using high-quality oil (5W-30 Total INEO ECS) greatly aid longevity.
The biggest issues are turbocharger bearing wear (especially pre-2014), direct injector coking leading to misfires, and timing chain guide wear. Other complaints include lambda sensor degradation and occasional EGR faults. These are well-documented in PSA service bulletins and technical reports.
This 1.6L turbo petrol was used in performance and premium Citroen models. It appeared in the DS3 (Racing, Performance), DS4 (THP 200), and C4 Picasso (THP 155/200). The engine was also shared with Peugeot (308 GT), DS (DS4), and Opel (Astra OPC) under PSA Group platforms. All variants are Euro 5 or Euro 6 compliant depending on model year.
Yes. The EP6DT responds well to ECU remapping. Stage 1 tunes typically gain +30–40 kW safely, as the stock turbo and internals handle increased boost. Supporting mods like intercooler upgrades and exhausts allow further gains. However, over-tuning without cooling improvements risks turbo failure or detonation, especially on lower-octane fuel.
Moderate. In a DS3 or C4 Picasso (200 PS version), typical consumption is ~9.5 L/100km (city) and ~6.2 L/100km (highway), or about 38 mpg UK combined. Real-world figures depend heavily on driving style. Expect 35–42 mpg (UK) on mixed roads for a healthy EP6DT. Aggressive driving reduces economy significantly.
Yes. The EP6DT is an interference engine. If the timing chain fails or jumps, pistons can strike open valves, causing severe internal damage. That's why chain maintenance is critical—any rattling at cold start should be investigated immediately to prevent catastrophic engine failure.
PSA specifies Total Quartz INEO ECS 5W-30 synthetic oil. Always use a high-temperature-stable oil designed for turbocharged direct-injection engines and change it every 15,000 km (or sooner under severe conditions) to protect the turbocharger and timing system from oil coking and wear.
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