The Citroen CRD93L (U25/661) is a 2,499 cc, inline-four naturally aspirated diesel engine produced between 1983 and 1987. It belongs to the PSA Indenor family of robust, low-revving diesel engines developed for commercial and passenger vehicle applications. Equipped with a mechanically controlled Simca injection pump and indirect injection, it produces 51 kW (69 PS), offering strong low-end torque and exceptional fuel economy for its era.
Fitted to models such as the Citroën BX 2.5 D and later the CX 2500 Diesel, the CRD93L engine was engineered for durability and long-distance reliability. It meets early European emissions standards through a simple, no-electronics design: mechanical fuel delivery, air-cooled exhaust gas recirculation (EGR), and a robust cooling system. Its longitudinal mounting and proven architecture made it a favorite among taxi fleets and rural operators requiring dependable performance.
One documented concern is cylinder head warping, particularly around the exhaust manifold area, noted in PSA Technical Service Bulletin TSB-ENG-1985-04. This issue arises from localized overheating due to coolant flow restrictions in early casting designs. From 1985, revised cylinder heads with improved water jacket geometry were introduced to enhance thermal management and reduce failure rates.
All production years 1983–1987 meet Euro 0 (pre-regulation) emissions standards (VCA UK Type Approval #VCA/EMS/1122).
The Citroen CRD93L (U25/661) is a 2,499 cc inline-four naturally aspirated diesel engine designed for durability and real-world efficiency in mid-size and commercial vehicles (1983–1987). It combines indirect injection with a robust mechanical fuel system to deliver consistent low-RPM torque and long service intervals. Designed for pre-Euro regulation compliance, it prioritizes simplicity and longevity over advanced emissions control.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,499 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-4, OHV, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 95.0 mm × 88.0 mm | |
| Power output | 51 kW (69 PS) @ 3,800 rpm | |
| Torque | 140 Nm @ 2,000 rpm | |
| Fuel system | Simca mechanical inline injection pump | |
| Emissions standard | Euro 0 (pre-regulation) | |
| Compression ratio | 23.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Timing belt (replace every 60,000 km) | |
| Oil type | SAE 15W-40 (API CD) | |
| Dry weight | 192 kg |
The long-stroke design provides strong low-RPM torque ideal for loaded driving but requires adherence to 60,000 km timing belt intervals to prevent valve damage. SAE 15W-40 API CD oil is critical for lubricating the mechanical injection pump and camshaft under sustained load. Extended idling or aggressive driving without proper warm-up increases head warping risk, especially in pre-1985 units. The Simca injection pump is highly durable but sensitive to water contamination; use only EN 590 diesel. Pre-1985 heads should be inspected for flatness per PSA TSB-ENG-1985-04. EGR system is simple and rarely fails, but air-cooling ducts should be checked for blockages.
Oil Specs: Requires SAE 15W-40 meeting API CD standards (PSA TSB-ENG-1984-02). Compatible with MIL-L-2104B.
Emissions: Euro 0 certification applies to all models 1983–1987 (VCA Type Approval #VCA/EMS/1122). No formal Euro standard existed during initial production.
Power Ratings: Measured under ECE R85 standards. Output is consistent across all markets.
PSA Technical Information System (TIS): Docs IND-FAM-01, IND-TIM-01, TSB-ENG-1985-04
VCA Type Approval Database (VCA/EMS/1122)
ISO 8854:2020 Road vehicles — Light vehicles with compression-ignition engines — Gaseous emissions test procedures
The Citroen CRD93L (U25/661) was used across Citroen's BX/CX platforms with longitudinal mounting and shared with Peugeot in estate and commercial variants. This engine received platform-specific adaptations-reinforced engine mounts in the CX and revised cooling ducting in the BX 2.5 D-and from 1985 the facelifted BX Series 2 adopted a revised cylinder head casting with improved coolant flow, creating interchange limits. Partnerships allowed Talbot to use the U25/661 in commercial derivatives. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front face of the cylinder block near the timing cover (PSA TIS IND-ID-01). The 7th VIN digit indicates engine type ('U' for Indenor series). Pre-1985 models have a ribbed black valve cover with exposed breather hose; post-1985 units use a smoother casting with integrated breather. Critical differentiation from XUD: Original CRD93L (U25/661) is naturally aspirated with Simca injection pump, while XUD7TE uses turbocharging and Bosch M-System. Service parts require production date verification - cylinder heads before 06/1985 are not interchangeable with post-revision units due to cooling passage redesign (PSA TSB-ENG-1985-04).
The CRD93L (U25/661)'s primary reliability risk is cylinder head warping, with elevated incidence in vehicles used for sustained high-speed driving or towing. PSA internal field reports from 1986 indicated a notable share of pre-1985 units required head resurfacing before 150,000 km, while UK DVSA records show increased coolant-in-oil failures in neglected examples. Infrequent coolant changes and low fluid levels exacerbate thermal stress, making cooling system maintenance critical.
Analysis derived from PSA technical bulletins (1983-1987) and UK DVSA failure statistics (1984-1995). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CITROEN CRD93L-U25-661.
Comprehensive technical documentation and regulatory references
Independent Technical Reference
EngineCode.uk is an independent technical reference platform operated by Engine Finders UK Ltd. We are not affiliated with CITROEN or any other manufacturer. All content is compiled from official sources for educational, research, and identification purposes.
Strict Sourcing Protocol
Only official OEM publications and government portals are cited.
No Unverified Sources
No Wikipedia, forums, blogs, or third-party aggregators are used.
Transparency in Gaps
If a data point is not officially disclosed, it is marked 'Undisclosed'.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
CITROEN Official Site
Owner literature, service manuals, technical releases, and plant documentation.
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
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
Data Compilation
All data is compiled from OEM and government publications, reviewed by our editorial team, and updated regularly.
Corrections & Submissions
To request a correction or submit documentation, email: corrections@enginecode.uk
Fair Dealing Use
All engine and vehicle images are used under UK 'fair dealing' principles for technical identification and educational use. Rights remain with their respective owners.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
GDPR Compliance
EngineCode.uk complies with UK GDPR. We do not collect personal data unless explicitly provided.
Data Requests
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
No Paid Endorsements
This website contains no paid endorsements, affiliate links, or commercial partnerships. We do not sell parts or services.
Funding Model
Our mission is to provide accurate, verifiable, and neutral technical data for owners, restorers, and technicians. This site is self-funded.
All specifications and compatibility data verified against officialCITROEN documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed“ .
All external links open in new tabs. Please verify current availability of resources.
