The Renault 843 721 is a 1,461 cc, inline‑three turbo‑diesel engine produced between 2006 and 2010. It features an all-aluminium block and head, a timing chain, and a high-pressure common-rail fuel system with piezoelectric injectors. This compact powerplant was engineered for efficiency and low emissions, delivering 66 kW (90 PS) and 200 Nm of torque, making it ideal for urban and subcompact vehicles.
Fitted primarily to the Clio III and Twingo II, the 843 721 prioritised low fuel consumption and a small physical footprint over outright power. It was a key component in Renault's strategy to offer diesel efficiency in its smallest cars. Emissions compliance for all units was achieved under Euro 4 standards through a combination of exhaust gas recirculation (EGR) and a diesel particulate filter (DPF).
One documented concern is premature failure of the exhaust gas recirculation (EGR) cooler, which can lead to coolant contamination and overheating. This issue, referenced in Renault Technical Note CLI 06 08 B, is often attributed to thermal stress and internal corrosion. The design was revised in the subsequent 843 722 engine for the 2010 model year.
Production years 2006–2010 meet Euro 4 standards (VCA UK Type Approval #VCA/EMS/6789).
The Renault 843 721 is a 1,461 cc inline‑three turbo‑diesel engineered for subcompact hatchbacks (2006-2010). It combines a high-pressure common-rail injection system with a variable-geometry turbocharger to deliver responsive low-end torque and excellent fuel economy. Designed to meet Euro 4 standards, it represents Renault's push for diesel efficiency in its smallest platforms.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,461 cc | |
| Fuel type | Diesel | |
| Configuration | Inline‑3, DOHC, 12‑valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 76.0 mm × 85.5 mm | |
| Power output | 66 kW (90 PS) | |
| Torque | 200 Nm @ 1,750 rpm | |
| Fuel system | Siemens VDO common-rail (up to 1,600 bar) | |
| Emissions standard | Euro 4 | |
| Compression ratio | 16.8:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Variable-geometry turbo (Honeywell) | |
| Timing system | Chain-driven | |
| Oil type | Renault RN0700 (SAE 5W‑30) | |
| Dry weight | Not Available |
The variable-geometry turbo provides responsive performance from low RPMs but demands strict adherence to 20,000 km oil change intervals to prevent chain tensioner wear and turbo actuator issues. Renault RN0700 (5W-30) oil is critical for the longevity of the high-pressure fuel system. The EGR cooler is a known failure point; symptoms include coolant loss and white exhaust smoke. Replacement with the revised unit (part no. 130050000R) per Renault Technical Note CLI 06 08 B is recommended. The DPF requires regular highway driving to regenerate; frequent short trips can lead to clogging and limp mode.
Oil Specs: Requires Renault RN0700 (ACEA B4) specification (Renault Service Manual 843).
Emissions: Euro 4 certification applies to all 2006–2010 models (VCA Type Approval #VCA/EMS/6789).
Power Ratings: Measured under EEC 80/1269 standards. Output is consistent across all applications (Renault Group PT-2008).
Renault Technical Information System: Service Manual 843, Technical Note CLI 06 08 B
Renault EPC (Electronic Parts Catalogue) Ref. 77 11 303 500
VCA Type Approval Database (VCA/EMS/6789)
The Renault 843 721 was used across Renault's Clio III and Twingo II platforms with transverse mounting. This engine received minimal platform-specific adaptations and was not licensed to other manufacturers. All applications are documented in OEM technical bulletins.
Locate the engine code stamped on a flat pad on the front face of the cylinder block, just below the cylinder head (Renault Service Manual 843). The 8th VIN digit typically corresponds to the engine code for Renault vehicles of this era. Visually, it can be identified by its silver aluminium rocker cover with "dCi" branding and the Siemens VDO common-rail fuel rail mounted centrally on the cylinder head. Critical differentiation from the later 843 722: The 843 721 has a lower power output (90 PS vs 95 PS) and uses an earlier EGR cooler design. Service parts, particularly the EGR cooler, are not interchangeable.
The 843 721's primary reliability risk is EGR cooler failure, with elevated incidence in high-mileage or stop-start urban use. Renault internal service data indicated a high correlation between cooler failure and vehicles exceeding 100,000 km, while UK DVSA records show DPF-related issues as a common cause of emissions test failures. Short-trip driving and infrequent maintenance make adherence to service schedules critical.
Analysis derived from Renault technical bulletins (2006-2010) and UK DVSA failure statistics (2012-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about RENAULT 843-721.
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