The Peugeot 6FZ (EW7J4) is a 1,749 cc, inline‑four naturally aspirated petrol engine produced between 2001 and 2008. It features a SOHC 16‑valve design with multipoint fuel injection, delivering a balance of economy and accessible performance. In standard applications, it produces 77 kW (105 PS), engineered for dependable daily driving in compact and mid — size vehicles.
Fitted to models like the Peugeot 307, 406, and Citroën C5, the 6FZ was designed for smooth, linear p…
Production years 2001–2008 meet Euro 3 standards .
The Peugeot 6FZ (EW7J4) is a 1,749 cc inline‑four naturally aspirated petrol engineered for compact and mid-size sedans/estates (2001-2008). It combines multipoint fuel injection with a single overhead camshaft to deliver smooth, predictable power and good fuel economy. Designed to meet Euro 3 standards, it prioritizes reliability and low-cost ownership.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,749 cc | |
Fuel type | Petrol | |
Configuration | Inline‑4, SOHC, 16‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 82.7 mm × 81.4 mm | |
Power output | 77 kW (105 PS) | |
Torque | 155 Nm @ 4,000 rpm | |
Fuel system | Siemens multipoint injection | |
Emissions standard | Euro 3 | |
Compression ratio | 10.5:1 | |
Cooling system | Water‑cooled | |
Turbocharger | None | |
Timing system | Belt (front‑mounted) | |
Oil type | PSA B71 2290 (SAE 10W‑40) | |
Dry weight | 125 kg |
The Peugeot 6FZ (EW7J4) was used across PSA Group's PF2 platform with transverse mounting. This engine received platform-specific adaptations-revised engine mounts for the 406 and specific exhaust routing for the C5-creating minor interchange considerations. All adaptations are documented in OEM technical bulletins.
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The 6FZ's primary reliability risk is inlet manifold failure, with elevated incidence in vehicles over 100,000 km. Peugeot service data indicates a notable number of replacements under warranty, while owner reports frequently cite coolant loss or rough idle as precursors. Adherence to the timing belt replacement schedule and prompt manifold replacement are critical.
Analysis derived from manufacturer technical service bulletins and industry workshop records. Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The 6FZ is generally a simple and reliable engine for long-term use if maintained correctly. Its main weakness is the plastic inlet manifold, which can crack and cause coolant leaks. The timing belt is critical and must be replaced on schedule. Using the correct 10W-40 oil and adhering to service intervals is essential for maximizing longevity.
The most frequent issues are plastic inlet manifold cracking causing coolant leaks, timing belt failure if not replaced on time, and ignition coil pack failures leading to misfires. Oil leaks from the front crankshaft seal are also common on higher-mileage engines. These are covered in Peugeot service documentation.
The 6FZ (EW7J4) 1.8 16V engine was used in the Peugeot 307 and 406 from 2001 to 2008. It was also fitted to the equivalent Citroën C5 during the same period. It was not used in smaller PSA vehicles like the 206 or larger models like the 607.
The 6FZ is not a common tuning candidate due to its SOHC design and modest output. Minor gains are possible through intake and exhaust modifications, but significant power increases are impractical without forced induction. It’s best suited as a reliable, economical daily driver.
Real-world fuel economy is very good for its era. In a Peugeot 307, expect around 7.5 L/100km (38 mpg UK) in combined driving. Highway cruising can yield 6.0-6.5 L/100km (43-47 mpg UK), while city driving may be 9.5-10.5 L/100km (27-30 mpg UK). Results vary with driving style and vehicle condition.
Yes. The 6FZ is an interference engine. If the timing belt were to fail or jump, the pistons would collide with the open valves, causing catastrophic internal damage. This is why replacing the belt, tensioner, and idlers at the 30,000 km interval is absolutely critical.
Peugeot mandates oil meeting the PSA B71 2290 specification, typically a 10W-40 mineral or semi-synthetic. Using the correct oil is vital for protecting the valve train and ensuring proper lubrication. Always change the oil and filter at the recommended intervals.
Comprehensive technical documentation and regulatory references
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Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
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