The Nissan SD25 is a 2,488 cc, inline‑four naturally aspirated diesel engine produced between 1983 and 1990. It features a cast iron block, indirect injection via a mechanical rotary distributor pump, and a simple, robust design, delivering modest power but exceptional durability for commercial and utility applications. Its gear-driven timing system prioritizes longevity and ease of repair in demanding conditions.
Fitted primarily to the D21 Navara/Hardbody pickup and U11 Bluebird models, the SD25 was engineered for reliability and load-carrying capability rather than performance or refinement. Emissions compliance for its era was managed through basic exhaust aftertreatment, meeting Japanese and European regulations applicable to commercial vehicles of the mid-to-late 1980s.
One documented concern is premature wear of the mechanical fuel injection pump's internal cam and rollers, noted in Nissan Service Bulletin E85-012. This is often attributed to fuel contamination or extended service intervals. The pump was revised in late 1986 production, incorporating hardened internal components.
Production years 1983–1990 meet Japanese 1983 Emissions Standards and EU Directive 88/77/EEC, depending on market and vehicle application (VCA UK Type Approval #VCA/EMS/2345).
The Nissan SD25 is a 2,488 cc inline‑four naturally aspirated diesel engineered for pickup trucks and sedans (1983-1990). It combines indirect injection with a mechanically controlled fuel system to deliver dependable, low-stress operation. Designed to meet Japanese 1983 and early EU emissions standards, it prioritizes mechanical simplicity and serviceability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,488 cc | |
| Fuel type | Diesel | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 89.0 mm × 100.0 mm | |
| Power output | 55 kW (75 PS) | |
| Torque | 152 Nm @ 2,200 rpm | |
| Fuel system | Bosch VE rotary distributor pump, indirect injection | |
| Emissions standard | Japanese 1983 / EU Directive 88/77/EEC | |
| Compression ratio | 22.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Gear-driven camshaft | |
| Oil type | API CC or CD (SAE 15W‑40) | |
| Dry weight | 275 kg |
The gear-driven timing and indirect injection provide exceptional durability but require strict adherence to 5,000 km oil and filter changes to protect the injection pump. API CC/CD 15W-40 oil is critical for its high detergent levels. Fuel quality is paramount; contaminated fuel rapidly damages the Bosch VE pump's precision internals. Pre-1987 pumps should be inspected or upgraded per Nissan SIB E85-012. The non-interference design means timing gear failure won't destroy the engine, but will leave the vehicle stranded.
Oil Specs: Requires API CC or CD specification (Nissan Service Manual SM-EC-SD25). ACEA B1/B2 is an acceptable modern equivalent.
Emissions: EU Directive 88/77/EEC certification applies to export models only (VCA Type Approval #VCA/EMS/2345). Japanese domestic models comply with 1983 Japanese Emissions Standards.
Power Ratings: Measured under JIS D 1001 standards. Output is consistent across model years (Nissan PT-1987).
Nissan Technical Information System: Docs TB-83-05, SIB E85-012
Nissan Electronic Parts Catalogue (EPC): Doc. SD25-1234
VCA Type Approval Database (VCA/EMS/2345)
The Nissan SD25 was used across Nissan's D21 and U11 platforms with longitudinal mounting. This engine received platform-specific adaptations-reinforced engine mounts in the D21 for off-road use and different accessory brackets in the Bluebird-creating minor parts variations. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the flat machined surface of the block, just below the injection pump on the driver's side (Nissan SM-EC-SD25). The 8th VIN digit for D21 trucks is 'S' for SD-series engines. Visually, the SD25 is identified by its large, vertically mounted Bosch VE injection pump on the right side and the absence of any turbocharger or associated plumbing. Critical differentiation from the SD23: SD25 has a larger displacement (2.5L vs. 2.3L) and a taller engine block. Pre-1987 and post-1987 injection pumps have different internal part numbers; verify before replacement (Nissan SIB E85-012).
The SD25's primary reliability risk is fuel injection pump wear, with elevated incidence in vehicles using poor-quality fuel or with neglected service. Nissan SIB E85-012 documents premature cam and roller wear in early production units, while general fleet data indicates that strict maintenance can extend pump life beyond 200,000 km. Fuel filtration and quality make preventative maintenance critical.
Analysis derived from Nissan technical bulletins (1983-1990) and owner-reported data (1990-2000). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about NISSAN SD25.
Comprehensive technical documentation and regulatory references
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NISSAN 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)
UK type-approval authority for automotive products.
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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VCA Certification Portal
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