The Renault F3N 723 is a 1,721 cc, inline‑four petrol engine produced between 1985 and 1996. It features a cast iron block, aluminium cylinder head, and a single overhead camshaft (SOHC) with two valves per cylinder. This naturally aspirated unit was designed for durability and ease of maintenance in Renault's compact and mid — size vehicles of the era.
Fitted primarily to the Renault 21 (N10/N11) and occasionally the Renault 25 (B80), the F3N 723 was engineered for reliabl…
Production years 1985–1996 predate standardized Euro emissions regulations for passenger cars in the EU.
The Renault F3N 723 is a 1,721 cc inline‑four petrol engine engineered for compact and mid‑size sedans (1985-1996). It combines a robust cast iron block with a simple SOHC, 8-valve design to deliver adequate power and strong reliability. Designed for the pre-Euro emissions era, it prioritizes mechanical simplicity and cost-effective ownership.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,721 cc | |
Fuel type | Petrol | |
Configuration | Inline‑4, SOHC, 8‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 83.0 mm × 79.5 mm | |
Power output | 66–72 kW (89–97 PS) | |
Torque | 135–145 Nm @ 3,500 rpm | |
Fuel system | Carburetor or Single-point injection | |
Emissions standard | Pre-Euro | |
Compression ratio | 9.2:1 | |
Cooling system | Water‑cooled | |
Turbocharger | None | |
Timing system | Chain-driven camshaft | |
Oil type | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 135 kg |
The Renault F3N 723 was used across Renault's N10/N11 platforms with longitudinal mounting. This engine received platform-specific adaptations-primarily different engine mounts and accessory brackets for the Renault 21 sedan and saloon variants. All adaptations are documented in OEM technical bulletins.
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The F3N 723's primary reliability risk is camshaft and follower wear, with elevated incidence in high-mileage or poorly maintained engines. Renault workshop data indicates this was a frequent cause of top-end noise and reduced performance in neglected examples. Infrequent oil changes and the use of thin or synthetic oils make adherence to the specified 15W-40 mineral oil critical.
Analysis derived from Renault technical bulletins (1985-1996) and historical workshop data. 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 F3N 723 is fundamentally a robust and simple engine. Its long-term reliability heavily depends on meticulous maintenance, particularly using the correct 15W-40 mineral oil and changing it frequently to prevent camshaft wear. Well-cared-for examples can easily exceed 200,000 km.
The most frequent issues are camshaft/follower wear (due to poor maintenance), carburetor problems on early models, cooling system leaks from ageing hoses, and ignition system faults. These are well-documented in Renault's service literature for the N10 platform.
The F3N 723 was primarily used in the Renault 21 (N10/N11 chassis) from 1985 to 1994, across various trim levels (TS, TSE, RS, RSE). It was also fitted to the early Renault 25 (B80) TS model from 1985 to 1988.
Minor power gains are possible. Upgrades include a performance carburetor or exhaust manifold, and a mild camshaft profile. However, the SOHC, 8-valve design is a significant limit. Major power increases are not practical or cost-effective on this engine.
Fuel economy is moderate for its era. Expect around 9.0 L/100km (31 mpg UK) in combined driving for a carbureted Renault 21. Fuel-injected versions may be slightly more efficient. Real-world figures vary significantly with driving style and vehicle condition.
No. The F3N 723 is a non-interference engine. If the timing chain were to fail, the pistons and valves would not collide, preventing catastrophic internal damage. This is a key design feature for its intended reliability.
Renault specifies a SAE 15W-40 mineral oil for the F3N 723. This is crucial for protecting the flat-tappet camshaft and followers. Modern synthetic or low-viscosity oils are not recommended and can accelerate wear.
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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