The Nissan RB25DE is a 2,492 cc, inline‑six naturally aspirated petrol engine produced between 1993 and 1998. It features a cast-iron block, aluminium cylinder head, and dual overhead camshafts with 24 valves. In standard form for the R33 Skyline and Stagea, it delivered 140 kW (190 PS) and 234 Nm of torque, providing smooth, linear power delivery ideal for grand touring.
Fitted primarily to the R33 Skyline sedan and coupe, as well as the WNC34 Stagea wagon, the RB25DE was engineered for refined performance and high-RPM responsiveness. Emissions compliance for its era was managed through electronic fuel injection and a three-way catalytic converter, meeting applicable Japanese and Australian Design Rule (ADR) standards of the mid-1990s.
One documented concern is premature wear of the timing chain tensioner and guides, referenced in Nissan Service Bulletin NTB95-067. This issue, often exacerbated by extended oil change intervals, can lead to chain rattle and potential timing jump. Nissan later revised the tensioner design for improved durability.
Production years 1993–1998 meet applicable Japanese and ADR standards for their model year (VCA UK Type Approval not applicable for this non-EU market engine).
The Nissan RB25DE is a 2,492 cc inline‑six naturally aspirated petrol engine engineered for sports sedans and wagons (1993-1998). It combines electronic fuel injection with DOHC 24-valve architecture to deliver smooth, high-revving power and refined grand touring capability. Designed to meet 1990s emissions standards, it balances performance with the technology of its era.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,492 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 86.0 mm × 71.5 mm | |
| Power output | 140 kW (190 PS) @ 6,000 rpm | |
| Torque | 234 Nm @ 4,800 rpm | |
| Fuel system | Electronic Fuel Injection (Multi-point) | |
| Emissions standard | 1990s Japanese / ADR standards | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven (single-row) | |
| Oil type | SAE 10W-30 or 10W-40 | |
| Dry weight | 195 kg |
The DOHC 24-valve design provides a broad, smooth powerband but requires strict 5,000-8,000 km oil changes to prevent timing chain tensioner wear. Using high-quality 10W-40 oil is recommended for high-RPM protection. The 10.0:1 compression ratio allows use of regular unleaded fuel in most markets. The single-row timing chain is generally robust but the tensioner and nylon guides are wear items; listen for rattle on cold start. The EFI system is reliable but sensitive to fuel filter neglect; replace every 40,000 km.
Oil Specs: Recommends SAE 10W-30 or 10W-40 (Nissan Owner's Manual R33 Skyline, 1995). Modern semi-synthetic 10W-40 is preferred for high-RPM durability.
Emissions: Meets 1990s Japanese and ADR standards (Nissan Service Bulletin NTB95-067). Not certified for EU markets.
Power Ratings: Measured under SAE net standards. Output is for stock Japanese-spec R33 Skyline (Nissan TIS Doc. RB-25DE-04).
Nissan Technical Information System (TIS): Docs RB-25DE-01, RB-25DE-02, RB-25DE-03
Nissan Electronic Parts Catalog (EPC): Doc. RB-2492
Nissan Service Bulletin: NTB95-067
Nissan Owner's Manual: Skyline (R33), 1995 Model Year
The Nissan RB25DE was used exclusively in Nissan's R33/WNC34 platforms with longitudinal rear-wheel-drive mounting. This engine received specific adaptations for the Stagea wagon, including a unique engine wiring harness and accessory bracketry. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front face of the cylinder block, near the crankshaft pulley (Nissan TIS RB-25DE-01). The 8th VIN digit for RB25DE-equipped R33 Skylines is 'D'. Visually, it is distinguished from the turbocharged RB25DET by the absence of a turbocharger, intercooler, and associated piping. The intake manifold is also unique to the DE variant. Critical differentiation: The RB25DE uses a different ECU and has a higher compression ratio than the RB25DET.
The RB25DE's primary reliability risk is timing chain tensioner and guide wear, with elevated incidence in vehicles subjected to high-RPM use or infrequent oil changes. Nissan Service Bulletin NTB95-067 details the issue, while owner reports frequently cite ignition coil failure as a secondary cause of misfires. Adherence to strict oil change intervals and using quality oil make chain longevity critical.
Analysis derived from Nissan technical bulletins (1993-1998) and owner-reported failure data (1999-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about NISSAN RB25DE.
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Regulation (EC) No 715/2007
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