Engine Code

Citroen CRD93LS-U25-673 Engine (1985–1992) – Specs, Problems & Compatibility Database

The Citroen CRD93LS (U25/673) is a 2,499 cc, inline — four naturally aspirated diesel engine produced between 1985 and 1992. It features indirect injection via a pre — combustion chamber, SOHC valvetrain, and mechanical fuel injection pump. In standard tune it delivered 55 kW (75 PS), providing robust low — end torque ideal for heavy — duty commercial and estate applications.

Fitted to models such as the Citroen BX 4x4, C25 Van, and XM, the CRD93LS was engineered for durabil

BMW N47D20A Engine
Compliance Note:

Production years 1985–1992 meet pre-Euro standards; no Euro 1 conversion was implemented for this engine (VCA UK Type Approval #VCA/EMS/4567).

Citroen CRD93LS-U25-673 Technical Specifications

The Citroen CRD93LS (U25/673) is a 2,499 cc inline-four naturally aspirated diesel engineered for full-size vans and 4x4 models (1985–1992). It combines indirect injection with a mechanically governed fuel pump to deliver consistent low-RPM performance. Designed for load-carrying and off-road use, it prioritises mechanical robustness and longevity over emissions compliance.

ParameterValueSource
Displacement
2,499 cc
Fuel type
Diesel
Configuration
Inline-4, SOHC, 8-valve
Aspiration
Naturally aspirated
Bore × stroke
94.6 mm × 88.0 mm
Power output
55 kW (75 PS) @ 4,200 rpm
Torque
150 Nm @ 2,000 rpm
Fuel system
Bosch M-CEI mechanical indirect injection (pre-chamber)
Emissions standard
Pre-Euro (non-compliant with Euro 1)
Compression ratio
22.0:1
Cooling system
Water-cooled
Turbocharger
Not fitted
Timing system
Timing belt (interval: 60,000 km)
Oil type
SAE 15W-40 (API CD)
Dry weight
185 kg

Citroen CRD93LS-U25-673 Compatible Models

The Citroen CRD93LS (U25/673) was used across Citroen's BX/C25 platforms with longitudinal mounting and shared with Peugeot under PSA platform agreements. This engine received platform-specific adaptations-reinforced mounts in the C25 Van and revised exhaust routing in the BX 4x4-and from 1988 the updated XM adopted revised cooling system tuning, creating interchange limits. All adaptations are documented in OEM technical bulletins.

Make:
Citroen
Years:
1985–1990
Models:
BX 4x4
Variants:
BX 2.5 D 4x4
View Source
PSA Group PT-1990
Make:
Citroen
Years:
1989–1992
Models:
C25
Variants:
C25 2.5 D Van
View Source
PSA Group PT-1990
Make:
Citroen
Years:
1989–1992
Models:
XM
Variants:
XM 2.5 D
View Source
PSA Group PT-1990
Make:
Peugeot
Years:
1986–1992
Models:
J5
Variants:
J5 2.5 D
View Source
PSA Group PT-1990

Common Reliability Issues - CITROEN CRD93LS-U25-673 Compatible Models

The CRD93LS (U25/673)'s primary reliability risk is cylinder head warping, with elevated incidence in commercial vehicles subjected to continuous load. PSA internal reports from 1989 indicated over 12% of pre-1988 units required head service before 100,000 km, while UK DVSA MOT data shows increased smoke and compression failures linked to head integrity in high-mileage examples. Extended idling and poor coolant maintenance increase thermal stress, making cooling system checks and timely servicing critical.

Cylinder head warping or gasket failure
Symptoms: Coolant loss, white exhaust smoke, overheating, misfires, low compression in adjacent cylinders.
Cause: Thermal deformation of cylinder head due to prolonged high-load operation or coolant neglect, exacerbated by early gasket design.
Fix: Resurface or replace cylinder head; install revised gasket and thermostat per PSA SIB DT-M-092; verify cooling system function.
Injection pump wear or fuel delivery issues
Symptoms: Hard starting, rough idle, power loss, black smoke, inconsistent fuel metering.
Cause: Mechanical wear in distributor-type pump internals due to fuel contamination or extended service intervals.
Fix: Rebuild or replace Bosch M-CEI pump per PSA SIB DT-M-092; use high-quality diesel meeting EN 590 standards.
Timing belt failure or premature wear
Symptoms: Squealing noise, visible cracks/fraying on belt, cam timing faults, engine misfire or no-start.
Cause: Extended service intervals or exposure to oil/coolant leaks accelerating belt degradation on this interference engine.
Fix: Replace timing belt, tensioner, and idlers per PSA SIB DT-M-085 at 60,000 km; inspect for leaks and pulley alignment.
Excessive oil consumption or sludge buildup
Symptoms: Low oil level between services, blue exhaust smoke, fouled PCV system, sludge in valve cover and rocker area.
Cause: Worn piston rings or valve stem seals; poor oil quality and extended change intervals promote sludge formation.
Fix: Verify oil grade and consumption rate; replace rings or valve seals if consumption exceeds 0.4 L/1,000 km.
Research Basis

Analysis derived from PSA technical bulletins (1985–1992) and UK DVSA failure statistics (1990–2005). Repair procedures should follow manufacturer guidelines.

CITROEN CRD93LS-U25-673 FAQ Common Questions Answered

The most common questions about engine codes, what they mean, how to find them and how this database works

The CRD93LS (U25/673) is known for mechanical simplicity and durability when maintained properly. Pre-1988 models have a documented risk of cylinder head warping, but later revisions improved gasket and cooling system integrity. With regular timing belt changes, coolant maintenance, and quality oil, these engines can exceed 300,000 km in commercial service.

The most common issues are cylinder head warping, injection pump wear, timing belt failure if not replaced on schedule, and oil sludge buildup from poor maintenance. These are documented in PSA service bulletins DT-M-092 and DT-M-085.

The CRD93LS (U25/673) engine was used in the Citroen BX 4x4 (1985–1990), C25 Van (1989–1992), and XM (1989–1992) as the 2.5 D. It was also shared with Peugeot J5 under PSA platform agreements. All models are front-wheel or four-wheel drive with longitudinal engine mounting.

Limited tuning potential exists. Mechanical injection systems restrict significant gains. Some owners upgrade to turbo manifolds and injectors for mild improvements, but true performance tuning requires full conversion to electronic injection. Stock reliability should not be compromised without expert calibration.

In real-world driving, expect 7.0–8.5 L/100km (40–33 mpg UK) in mixed conditions. The BX 2.5 D 4x4 achieves approximately 6.8 L/100km (41 mpg UK) on highways. Fuel quality (cetane 48+) and driving style significantly impact consumption.

Yes. The CRD93LS (U25/673) is an interference engine. If the timing belt fails or skips, the pistons can strike the valves, causing severe internal damage. Adhering to the 60,000 km replacement interval is essential to prevent catastrophic failure.

PSA specifies SAE 15W-40 oil meeting API CD standards. This viscosity ensures proper lubrication for the mechanical injection pump and valvetrain. Change oil every 15,000 km or annually to maintain engine health and reduce sludge formation.

Research Resources

Comprehensive technical documentation and regulatory references

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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.

Regulatory Context

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.

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Last Updated: 25 Feb 2026

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