The Peugeot DKZ (XU9JAZ) is a 1,905 cc, inline‑four naturally aspirated petrol engine produced between 1986 and 1992. It features a cast iron block, aluminium head, and belt — driven dual overhead camshafts (DOHC). This engine was part of PSA's XU family, known for its robust design and delivering a balance of performance and reliability for its era.
Fitted primarily to the Peugeot 405 Mi16 and certain Citroën BX 16V models, the DKZ was engineered for spirited driving, offe…

Production years 1986–1992 meet applicable French and EU emissions standards for passenger vehicles of that era (UTAC Type Approval).
The Peugeot DKZ (XU9JAZ) is a 1,905 cc inline‑four naturally aspirated petrol engine engineered for performance-oriented sedans and hatchbacks (1986-1992). It combines electronic fuel injection with a DOHC 16-valve cylinder head to deliver a high-revving, responsive powerband. Designed to meet late-1980s emissions regulations, it offered a compelling blend of performance and relative efficiency for its time.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,905 cc | |
Fuel type | Petrol | |
Configuration | Inline‑4, DOHC, 16‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 83.0 mm × 88.0 mm | |
Power output | 118 kW (160 PS) @ 6,500 rpm | |
Torque | 190 Nm @ 4,500 rpm | |
Fuel system | Bosch LE2-Jetronic electronic fuel injection | |
Emissions standard | Late 1980s EU standards | |
Compression ratio | 10.4:1 | |
Cooling system | Water‑cooled | |
Turbocharger | None | |
Timing system | Belt-driven (requires strict 60,000 km/4 yr replacement) | |
Oil type | 10W-40 or 15W-50 mineral/synthetic blend | |
Dry weight | Not available in public OEM docs |
The Peugeot DKZ (XU9JAZ) was used primarily in Peugeot's performance models with longitudinal mounting. This engine received specific tuning for the 405 Mi16, including a unique intake manifold and exhaust system, and was also fitted to the Citroën BX 16V. All adaptations are documented in OEM technical bulletins.
The DKZ's primary reliability risk is timing belt or tensioner failure, which will destroy the engine due to its interference design. PSA service data and owner club records consistently highlight this as the most critical failure point. Neglecting the 60,000 km service interval or using incorrect oil viscosity significantly increases the risk of major mechanical failure.
Analysis derived from PSA technical bulletins (1986-1992) and aggregated data from Peugeot/Citroën owner club technical forums. Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The DKZ can be very reliable long-term if meticulously maintained, especially regarding the timing belt. Its main weakness is the interference design combined with a belt-driven system. With strict adherence to service intervals and using correct oil, these engines are known to exceed 200,000 km without major issues.
The most critical problem is timing belt/tensioner failure leading to engine destruction. Other common issues include noisy hydraulic tappets, wear of the distributor drive belt, and coolant leaks from the water pump or hoses. All are well-documented in PSA service literature.
The DKZ engine is most famously found in the Peugeot 405 Mi16 (1987-1992). It was also used in the performance variant of the Citroën BX, known as the BX 16V (1988-1990). It is not found in standard 405 or BX models, which used lower-powered 8-valve XU engines.
Yes, the DKZ is a popular engine for tuning. Common stage 1 modifications include a free-flow exhaust, performance air filter, and ECU remap, yielding 10-20 kW gains. More extensive builds involve camshafts, head work, and individual throttle bodies for significantly higher outputs, leveraging its robust bottom end.
Fuel economy is moderate for its performance. Expect around 9.5-10.5 L/100km (27-25 mpg UK) in mixed driving for a 405 Mi16. Highway cruising can see figures closer to 7.5-8.0 L/100km (38-35 mpg UK), while aggressive driving will consume significantly more.
Yes. This is critically important. The DKZ is an interference engine. If the timing belt breaks or jumps, the pistons will collide with the open valves, causing severe and expensive internal engine damage. Regular belt changes are non-negotiable.
PSA originally specified 10W-40 or 15W-50 mineral or semi-synthetic oil. A modern, high-quality 10W-40 synthetic oil meeting ACEA A3/B4 specification is an excellent choice, offering better protection, especially under spirited driving conditions.
Comprehensive technical documentation and regulatory references
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PEUGEOT 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
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
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