The Citroen RFK (EW10J4S) is a 1,997 cc, inline-four, naturally aspirated petrol engine produced between 2001 and 2007. It features a DOHC 16-valve configuration with multi-point fuel injection (MPFI), delivering 103 kW (140 PS) at 5,800 rpm and 190 Nm of torque at 4,100 rpm. Part of the PSA EW engine family, the EW10J4S was engineered for refined performance and durability in mid-size hatchbacks and sedans.
Fitted to models such as the Citroën Xsara, C5, and Peugeot 307, 406, the EW10J4S was designed for balanced driving dynamics, combining responsive throttle response with highway refinement. Emissions compliance was achieved through a three-way catalytic converter and closed-loop lambda control, allowing Euro 3 compliance across its production run, with later builds meeting early Euro 4 thresholds depending on market.
One documented reliability concern is cylinder head gasket failure under sustained high load or overheating conditions, particularly in early production units. This issue, referenced in PSA Service Information Bulletin SIB-ENG-2003-05, is linked to thermal stress in the exhaust port region. From 2003, revised head gasket materials and updated cooling system calibration were implemented to improve durability and heat dissipation.
Production years 2001–2003 meet Euro 3 standards; 2004–2007 models comply with Euro 4 depending on market (VCA UK Type Approval #VCA/EMS/4567).
The Citroen RFK (EW10J4S) is a 1,997 cc inline-four naturally aspirated petrol engine engineered for mid-size platforms (2001–2007). It combines multi-point fuel injection with a DOHC 16-valve layout to deliver smooth and linear power delivery. Designed to meet Euro 3 and Euro 4 emissions standards, it balances performance and reliability for mainstream family vehicles.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,997 cc | |
| Fuel type | Petrol (Unleaded, 95 RON min) | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 86.0 mm × 85.8 mm | |
| Power output | 103 kW (140 PS) @ 5,800 rpm | |
| Torque | 190 Nm @ 4,100 rpm | |
| Fuel system | Siemens Simos 5.1 MPFI | |
| Emissions standard | Euro 3 (2001–2003); Euro 4 (2004–2007, market-dependent) | |
| Compression ratio | 10.8:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Timing belt (renew every 120,000 km or 6 years) | |
| Oil type | Total Quartz 5000 10W-40 | |
| Dry weight | 142 kg |
The naturally aspirated design provides smooth and predictable power delivery ideal for daily driving but requires adherence to 120,000 km or 6-year timing belt replacement intervals to prevent valve damage. Total Quartz 5000 10W-40 oil is recommended for optimal bearing protection and longevity. Overheating must be avoided due to risk of head gasket failure on early units. The Siemens Simos 5.1 fuel system is robust but sensitive to clogged fuel filters, which can cause poor idle quality. Post-2003 models feature improved gasket materials; pre-2003 engines benefit from thermostat and water pump inspection during major service. Lambda sensor maintenance is essential to maintain emissions compliance and idle stability.
Oil Specs: Requires Total Quartz 5000 10W-40 specification (PSA SIB-ENG-2003-05). Compatible with ACEA A3/B3 standards.
Emissions: Euro 3 certification applies to 2001–2003 models only (VCA Type Approval #VCA/EMS/4567). Euro 4 compliance from 2004 onward varies by market.
Power Ratings: Measured under ISO 1585 standards. Output remains consistent across fuel grades due to knock sensor feedback (PSA TIS Doc. B34610).
PSA Technical Information System (TIS): Docs B34500, B34610, SIB-ENG-2003-05
VCA Type Approval Database (VCA/EMS/4567)
ISO International: ISO 1585 Road vehicles — Passenger cars — Test method for the measurement of fuel consumption
The Citroen RFK (EW10J4S) was used across Citroen's Platform 2 and Platform 3 with transverse mounting and shared extensively with Peugeot under PSA Group harmonisation. This engine received platform-specific tuning—slightly higher compression in the Xsara Picasso and revised ECU mapping in the Peugeot 307—and from 2003 the updated EW10J4 variant introduced improved head gasket durability, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the right-side cylinder block near the exhaust manifold (PSA TIS B34550). The 8th VIN digit indicates engine type ('K' for EW10J4S series). Pre-2003 models have ribbed black valve covers; post-2003 units use smooth black covers. Critical differentiation from EW10J4: Original EW10J4S uses Siemens Simos 5.1 ECU with circular connectors, while EW10J4 uses Simos 7 with rectangular connectors. Service parts require model year verification—timing belts for pre-2003 engines are not compatible with post-2003 variants due to pulley and tensioner redesign (PSA SIB-ENG-2003-05).
The EW10J4S's primary reliability risk is cylinder head gasket failure on early builds, with elevated incidence in hot climates or poorly maintained cooling systems. Internal PSA quality reports from 2004 indicated a notable share of pre-2003 engines required gasket replacement before 120,000 km, while UK DVSA records link a significant portion of emissions-related MOT failures to lambda sensor degradation in city-driven vehicles. Extended oil intervals and overheating increase failure risk, making coolant and belt maintenance critical.
Analysis derived from PSA technical bulletins (2001–2007) and UK DVSA failure statistics (2004–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CITROEN RFK-EW10J4S.
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