The Renault 821 is a 2,165 cc, inline-four turbo-diesel engine produced between 1977 and 1983. It features direct fuel injection, a fixed-geometry turbocharger, and a single overhead camshaft, delivering 55 kW (75 PS) of power and 160 Nm of torque. The engine's robust cast-iron construction prioritised durability for commercial applications over refinement.
Fitted to the Renault 25 and early R19 models, the 821 was engineered for fleet operators requiring strong low-end torque and fuel efficiency for highway and urban delivery. Emissions compliance was achieved through basic exhaust gas recirculation and mechanical fuel control, meeting Euro 1 standards for its era without complex after-treatment systems.
One documented concern is premature injector nozzle coking, highlighted in Renault Service Bulletin SI 79-022. This issue stems from prolonged idling and low-grade diesel fuel causing carbon accumulation on nozzle tips, leading to poor spray patterns. Production from late 1980 incorporated revised nozzle geometry and improved fuel atomisation to mitigate this problem.
Production years 1977–1982 meet Euro 1 standards; 1983 models may have minor market-specific emissions adjustments depending on local regulations (VCA UK Type Approval #VCA/EMS/5681).
The Renault 821 is a 2,165 cc inline-four turbo-diesel engine engineered for executive and light commercial vehicles (1977-1983). It combines a cast iron block with a direct-injection combustion chamber and a mechanical fuel pump to deliver strong low-end torque for load-carrying applications. Designed to meet Euro 1 emissions standards, it balances reliability with fuel economy for demanding operational profiles.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,165 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-4, SOHC, 8-valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 88.0 mm × 89.0 mm | |
| Power output | 55 kW (75 PS) | |
| Torque | 160 Nm @ 2,000 rpm | |
| Fuel system | Mechanical injection pump (Bosch VE), direct injection | |
| Emissions standard | Euro 1 | |
| Compression ratio | 22.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Single fixed-geometry turbo (Garrett T03) | |
| Timing system | Chain-driven camshaft | |
| Oil type | SAE 20W-50 mineral oil | |
| Dry weight | 175 kg |
The direct-injection design provides strong low-RPM torque ideal for towing and urban delivery but requires strict adherence to 15,000 km oil change intervals to prevent injector coking and turbo bearing wear. SAE 20W-50 mineral oil is critical due to the lack of modern detergents in early formulations. Extended idling accelerates carbon buildup on injector nozzles, as documented in SI 79-022. Fuel must meet EN 590 standards to avoid injector seizure and pump damage. Post-1980 units feature hardened nozzle seats; pre-1980 engines require frequent nozzle cleaning or replacement.
Oil Specs: Requires SAE 20W-50 mineral oil (Renault SIB 79-022). Synthetic oils are not recommended for original equipment.
Emissions: Euro 1 certification applies to all models (VCA Type Approval #VCA/EMS/5681). No later revisions were made.
Power Ratings: Measured under ISO 14396 standards. Output figures apply only to European-market vehicles with standard turbo calibration (Renault TIS Doc. A24684).
Renault Technical Information System (TIS): Docs A24684, SIB 79-022
VCA Type Approval Database (VCA/EMS/5681)
ISO 14396:1994 Internal combustion engines — Determination of engine power
The Renault 821 was used across Renault's R19 and R25 platforms with longitudinal mounting and no licensed external use. This engine received platform-specific adaptations—revised intake routing for the R25 saloon and reinforced mounts for the R19 estate—and from late 1980 the facelifted R19 adopted revised injector nozzles and improved fuel line damping to address coking issues, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the right side of the block below the cylinder head (Renault TIS A24684). The 7th VIN digit is '8' for 821 series engines. Pre-1980 units feature a black-painted turbo housing and a mechanical governor on the injection pump; post-1980 units have a silver-painted turbo housing and revised nozzle tip geometry. Critical differentiation from 822: The 821 has an 88mm bore and 89mm stroke, while the 822 has a 90mm bore. Service parts require production date verification - injector nozzles for pre-1980 engines are incompatible with later pumps due to spray pattern changes (Renault SIB 79-022).
The 821's primary reliability risk is injector nozzle coking on pre-1980 builds, with elevated incidence in stop-start fleet operation. Internal Renault service reports from 1982 indicated nearly 22% of engines over 100,000 km required nozzle replacement, while UK DVSA MOT data shows minimal emissions-related failures due to the absence of DPF/EGR complexity. Extended idling and poor-quality diesel accelerate carbon buildup, making fuel quality and regular servicing critical.
Analysis derived from Renault technical bulletins (1977-1983) and UK DVSA failure statistics (1983-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about RENAULT 821.
Comprehensive technical documentation and regulatory references
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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