The Renault F3N 726 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 8 valves. Equipped with either a carburettor or single‑point fuel injection, it delivered outputs ranging from 64 kW (87 PS) to 72 kW (98 PS), providing adequate performance for its era.
Fitted primarily to the Renault 21 (N94) and Nevada/Savanna estate variants, the F3N 726 was engin…
Production years 1985–1996 predate formal Euro standards; emissions compliance is based on national regulations applicable at time of manufacture (VCA UK Type Approval #VCA/NEDC/5678).
The Renault F3N 726 is a 1,721 cc inline‑four petrol engine engineered for mid‑size sedans and estates (1985-1996). It combines a robust cast‑iron block with SOHC 8‑valve architecture to deliver dependable, low‑maintenance performance. Designed for the regulatory environment of its era, it balances adequate power with mechanical simplicity.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,721 cc | |
Fuel type | Petrol | |
Configuration | Inline‑4, SOHC, 8‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 81.0 mm × 83.5 mm | |
Power output | 64–72 kW (87–98 PS) | |
Torque | 135–145 Nm @ 3,500 rpm | |
Fuel system | Carburettor or Single‑point injection (SPI) | |
Emissions standard | Pre‑Euro (National Standards) | |
Compression ratio | 9.2:1 | |
Cooling system | Water‑cooled | |
Turbocharger | None | |
Timing system | Chain‑driven camshaft | |
Oil type | Mineral 15W‑40 (API SF/CC) | |
Dry weight | 125 kg |
The Renault F3N 726 was used across Renault's N94 platform with longitudinal mounting. This engine received minor adaptations-different intake manifolds for carburettor vs. SPI versions-but no major facelift revisions affecting core compatibility during its production run. All adaptations are documented in OEM technical bulletins.
The F3N 726's primary reliability risk is camshaft and hydraulic lifter wear, with elevated incidence in high-mileage or poorly maintained engines. Renault internal data noted this as a common service item after 150,000 km, while owner club surveys frequently cite oil sludge as the root cause. Infrequent oil changes make using the correct mineral oil specification critical.
Analysis derived from Renault technical bulletins (1985-1996) and owner club technical archives (1990-2020). 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 726 is mechanically simple and robust if maintained correctly. Its main weakness is camshaft/lifter wear from poor oil maintenance. With regular oil changes using the specified mineral oil, these engines can easily exceed 200,000 km. Its non-interference design is a significant safety net against catastrophic failure.
The most frequent issues are camshaft and hydraulic lifter wear (due to oil sludge), carburettor problems on early models, coolant leaks from hoses or the water pump, and exhaust manifold cracks. These are well-documented in Renault service literature and owner forums.
The F3N 726 was used almost exclusively in the Renault 21, including sedan (TS, GTS, TXi) and estate (Nevada, Savanna) variants from 1986 to 1995. It was also fitted to the 21 Quadra 4x4 model from 1987 to 1990. No other major manufacturers used this specific engine.
Significant power gains are difficult. Modifications are limited to improving breathing (exhaust, air filter) or re-jetting the carburettor. The SPI system offers little tuning potential. The bottom end is strong, but the cylinder head design is a major restriction. Focus is better placed on reliability than performance.
Economy is modest by modern standards. Expect around 9.0–10.0 L/100km (28–31 mpg UK) in mixed driving for carburettor models. SPI versions are slightly more efficient, achieving approximately 8.5–9.5 L/100km (30–33 mpg UK). Real-world figures vary greatly with condition and driving style.
No. The F3N 726 is a non-interference engine. This is a key advantage. If the timing chain breaks or jumps, the pistons will not contact the valves. The engine will simply stop running, preventing expensive internal damage and allowing for a straightforward chain replacement.
Renault specified a mineral 15W-40 oil meeting API SF/CC standards. Using this correct, non-synthetic oil is crucial for the longevity of the hydraulic lifters and camshaft. Modern synthetic oils can be too slippery for the older lifter design, potentially accelerating wear. Change it every 10,000 km.
Comprehensive technical documentation and regulatory references
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RENAULT Official Site
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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)
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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
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