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 reliable, economical transportation. It offered adequate performance for its time, focusing on fuel efficiency and low running costs for fleet and private users. Emissions compliance for its production period was met through basic carburetion or early fuel injection systems.
One documented concern is premature wear of the camshaft and its followers, particularly in high-mileage or poorly maintained examples. This issue, noted in Renault's internal service documentation, is often linked to infrequent oil changes or the use of incorrect oil viscosity. The design was eventually superseded by more modern, multi-valve engines like the F3P and F3R series.
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 | SAE 15W-40 (Mineral) | |
| Dry weight | 135 kg |
The simple SOHC design provides adequate performance for city and highway driving but requires strict 10,000 km oil changes to prevent camshaft lobe wear. Using a quality 15W-40 mineral oil is critical due to the flat-tappet camshaft design. The timing chain is generally robust but should be inspected for slack every 80,000 km. Carbureted versions are sensitive to fuel quality and require periodic tuning. The engine's simplicity makes it easy to work on, but sourcing genuine parts for this discontinued model can be challenging.
Oil Specs: Requires SAE 15W-40 mineral oil specification (Renault Service Manual N10). Modern synthetic oils may not provide adequate protection for the flat-tappet camshaft.
Emissions: Pre-Euro certification applies to all production years (1985-1996) as standardized EU emissions regulations were not in force.
Power Ratings: Measured under SAE J1349 standards. Output varies between carbureted and injected variants (Renault Group PT-1990).
Renault Technical Information System (TIS): Docs TB-87-03, Service Manual N10
Renault EPC Catalogue
EU Regulation (EC) No 715/2007 (Historical Context)
SAE International: J1349 Engine Power Certification Standards
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.
Locate the engine code stamped on the front face of the cylinder block, just below the cylinder head (Renault TIS Doc. N10-01). The full code "F3N 723" should be clearly visible. Visually, it can be identified by its single camshaft cover and either a carburetor (Solex or Weber) or a single throttle body injection system on the intake manifold. Critical differentiation from the similar F2N: The F3N has a 1.7L displacement (83mm bore) versus the F2N's 1.6L (80mm bore). Service parts for the cylinder head and valvetrain are generally not interchangeable between F2N and F3N engines.
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.
Find answers to most commonly asked questions about RENAULT F3N-723.
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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