The Renault J7T 770 is a 2,068 cc, inline‑four turbocharged diesel engine produced between 1987 and 1996. It features a cast-iron block, indirect injection via pre-chambers, and a single overhead camshaft. Delivering 66 kW (90 PS), its robust construction prioritized durability and enhanced performance over its naturally aspirated sibling.
Fitted primarily to the Renault 25 and Renault 21, the J7T 770 was engineered for spirited driving and improved highway cruising. Emissions compliance for its era was managed through oxidation catalysts and exhaust gas recirculation (EGR), meeting French and European standards of the late 1980s.
One documented concern is premature failure of the turbocharger oil feed line gasket, leading to oil leaks and potential turbo bearing damage, as noted in Renault Technical Note NT J7T‑03. This issue is often linked to heat cycling and material degradation. Subsequent revisions introduced a reinforced gasket material and revised oil line routing to mitigate this failure mode.
All production years (1987–1996) meet applicable French and European emissions standards for their production year (No VCA UK Type Approval applicable for this era).
The Renault J7T 770 is a 2,068 cc inline‑four turbocharged diesel engineered for executive sedans (1987-1996). It combines indirect injection with SOHC valvetrain and a turbocharger to deliver enhanced low-end torque. Designed to meet contemporary French and European emissions standards, it balances performance with the proven reliability of indirect injection.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,068 cc | |
| Fuel type | Diesel | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 86.0 mm × 89.0 mm | |
| Power output | 66 kW (90 PS) | |
| Torque | 192 Nm @ 2,250 rpm | |
| Fuel system | Bosch VE mechanical injection with indirect pre-chamber | |
| Emissions standard | French/European standards (pre-Euro) | |
| Compression ratio | 22.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Garrett T2 (non-intercooled) | |
| Timing system | Chain | |
| Oil type | SAE 15W-40 mineral oil | |
| Dry weight | 195 kg |
The turbocharger provides significantly improved low-end torque ideal for overtaking but requires strict adherence to 10,000 km oil change intervals to prevent turbo bearing wear. Use of correct SAE 15W-40 mineral oil is critical for lubricating the mechanical injection pump and turbo. The turbo oil feed line gasket is a known wear item; replacement every 80,000 km or at timing chain service is recommended per Renault NT J7T-03. Allow engine to idle for 30-60 seconds after hard driving to cool turbo bearings.
Oil Specs: Requires SAE 15W-40 mineral oil (Renault SIB J7T-02). API CC specification minimum.
Emissions: Pre-dates formal Euro standards. Complied with French Decree 88-1039 and equivalent European directives.
Power Ratings: Measured under DIN 70020 standards. Output consistent across all markets (Renault TIS Doc. J7T-003).
Renault Technical Information System (TIS): Docs J7T-001, J7T-002, J7T-003, SIB J7T-01
French Journal Officiel Decree 88-1039 (Emissions)
DIN 70020: Road vehicles — Engine power measurement
The Renault J7T 770 was developed for Renault's 25 and 21 platforms with longitudinal mounting. This engine received platform-specific adaptations-reinforced engine mounts and upgraded cooling for the turbo-and no significant facelift revisions affecting core compatibility during its production run. The engine was exclusive to Renault Group vehicles. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the flat machined pad on the left side of the cylinder block, adjacent to the injection pump (Renault TIS J7T-ID). The 8th VIN digit typically corresponds to engine displacement ('7' for 2.1L). Visually, the engine is identifiable by its cast-iron block, single cam cover, prominent Bosch VE injection pump, and Garrett T2 turbocharger mounted on the exhaust manifold. Critical differentiation from naturally aspirated J7T 715: J7T 770 has a turbocharger, oil cooler, and different intake/exhaust manifolds. Service parts for turbo system are not interchangeable with non-turbo variants.
The J7T 770's primary reliability risk is turbocharger oil feed line gasket failure, with elevated incidence in vehicles exceeding 80,000 km without replacement. Renault internal service data indicates this is a leading cause of turbo bearing complaints, while owner club surveys show glow plug relay failures are common in cold climates. Extended service intervals make adherence to recommended maintenance critical.
Analysis derived from Renault technical bulletins (1987-1996) and Renault 21/25 owner club technical surveys. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about RENAULT J7T-770.
Comprehensive technical documentation and regulatory references
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RENAULT Official Site
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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)
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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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