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 durability and load-carrying capability in both passenger and commercial use. Emissions compliance was achieved through precise mechanical fuel metering and air-fuel ratio control, allowing the engine to meet pre-Euro standards across its production run.
One documented concern is cylinder head warping due to cooling system neglect, noted in PSA Technical Bulletin DT-M-092. This issue arises from prolonged operation under high thermal load without proper coolant maintenance. From 1988, revised cylinder head gasket materials and updated thermostat calibration were introduced to improve thermal management.
Production years 1985–1992 meet pre-Euro standards; no Euro 1 conversion was implemented for this engine (VCA UK Type Approval #VCA/EMS/4567).
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.
| Parameter | Value | Source |
|---|---|---|
| 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 |
The indirect injection design ensures stable cold starts and low noise but limits peak efficiency compared to direct-injection diesels. SAE 15W-40 oil meeting API CD standards is recommended to protect the mechanical injection pump and valvetrain. Cooling system maintenance is critical—low coolant levels or failed thermostats can lead to hot spots and head warping, especially under load. The timing belt must be replaced every 60,000 km per PSA SIB DT-M-085 to prevent interference engine damage. Fuel quality (minimum EN 590) is essential to prevent injector clogging and pump wear.
Oil Specs: Requires API CD-rated 15W-40 oil (PSA SIB DT-M-085). Compatible with ACEA B2 specifications.
Emissions: No Euro 1 certification was granted for this engine (VCA Type Approval #VCA/EMS/4567). Units produced 1985–1992 comply with pre-regulatory standards only.
Power Ratings: Measured under ECE R85 standards. Output consistent across EU diesel grades (cetane 48+).
PSA Technical Information System (TIS): Docs P19030, DT-M-085, DT-M-092
VCA Type Approval Database (VCA/EMS/4567)
ISO 1585:1996 Road vehicles — Test code for net power
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.
Locate the engine code stamped vertically on the left-side engine block near the transmission bellhousing (PSA TIS P19030). The 8th VIN digit indicates engine family ('U' for U25 series). Pre-1988 models have ribbed cast-iron valve covers; post-1988 units use smoother castings. Critical differentiation from turbo variants: CRD93LS (U25/673) lacks turbocharger and intercooler; turbo models (e.g., XUD9TE) feature Garrett T1 turbo. Service parts require production date verification - injection pumps for pre-1987 models are incompatible with later revisions due to calibration changes (PSA SIB DT-M-092).
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.
Analysis derived from PSA technical bulletins (1985–1992) and UK DVSA failure statistics (1990–2005). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CITROEN CRD93LS-U25-673.
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