The Peugeot XN1T is a 1,580 cc, inline‑four petrol engine produced between 1986 and 1992. It features a single overhead camshaft (SOHC) and two valves per cylinder, prioritising cost-effective manufacturing and adequate performance for its era. Equipped with a twin-choke carburettor for fuel delivery, it produces approximately 55 kW (75 PS) and 120 Nm of torque, offering a balance of drivability and fuel economy for compact family cars.
Fitted primarily to the Peugeot 309 and 405 models, the XN1T was engineered for dependable, everyday motoring with an emphasis on low-to-mid range torque for urban and highway use. Its character is defined by mechanical simplicity and smooth power delivery, rather than high-revving performance. Emissions control for its production period relied on basic engine tuning, exhaust gas recirculation (EGR), and a catalytic converter to meet prevailing French and EU standards.
One documented area for attention is the susceptibility of the twin-choke carburettor to wear and tuning drift, which can lead to uneven running or increased fuel consumption. Service documentation from the period, such as Peugeot Technical Bulletin TB-88-03, advises regular inspection and adjustment of the carburettor linkages and idle circuits to maintain optimal performance and prevent hesitation or stalling, particularly during warm-up.
Production years 1986–1992 meet pre-Euro emissions standards as per applicable French and EU regulations of the time (UTAC Type Approval records).
The Peugeot XN1T is a 1,580 cc inline‑four petrol engine engineered for compact family sedans and hatchbacks (1986-1992). It combines a simple SOHC valvetrain with carburetted fuel delivery to deliver smooth, predictable power and respectable fuel economy. Designed to meet the emissions standards of its era, it prioritises mechanical simplicity and ease of service.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,580 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 78.0 mm × 82.6 mm | |
| Power output | 55 kW (75 PS) @ 5,500 rpm | |
| Torque | 120 Nm @ 3,000 rpm | |
| Fuel system | Solex 35/35 DIDTA twin-choke carburettor | |
| Emissions standard | Pre-Euro (1980s/90s French/EU) | |
| Compression ratio | 9.2:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven camshaft | |
| Oil type | Mineral 15W-40 (API SF/CC) | |
| Dry weight | 105 kg |
The twin-choke carburettor provides a broad torque curve but demands periodic synchronization and cleaning to prevent running issues. Using the specified mineral oil (15W-40) is important for older engine seals and bearing clearances. The timing chain is generally robust but should be inspected for slack or noise around 120,000 km. Fuel quality is less critical than for modern engines, but clean, fresh petrol is recommended. The simple design makes many repairs DIY-friendly with basic tools.
Oil Specs: Requires mineral 15W-40 meeting API SF/CC specification (Peugeot Service Manual 170B). Modern synthetic oils may not be suitable for aged seals.
Emissions: Pre-Euro certification applies to all production years (UTAC Type Approval Records). No formal Euro standard existed during its production.
Power Ratings: Measured under DIN 70020 standards (Peugeot Group PT-1988). Output is consistent across model applications.
Peugeot Technical Information System: Bulletins TB-86-01, TB-88-03
Peugeot Electronic Parts Catalogue (EPC) Ref. 9616.XX
Peugeot Service Manual 170B (1987 Edition)
UTAC (Union Technique de l'Automobile) Type Approval Archives
The Peugeot XN1T was used across Peugeot's compact platforms with transverse mounting. This engine received minor platform-specific adaptations-primarily in ancillary bracketry and exhaust routing between the 309 and 405-but remained fundamentally interchangeable. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the flat boss at the front of the cylinder block, near the gearbox flange (Peugeot Service Manual 170B). The code "XN1T" will be clearly visible. Visually, it can be identified by its twin-choke Solex carburettor and distributor-based ignition system. Critical differentiation from the larger XU5 (1.6L fuel-injected) engine is the presence of the carburettor and specific engine block casting. Ancillary components like the alternator bracket may differ between 309 and 405 applications, but the core engine is identical.
The XN1T's primary reliability consideration is carburettor maintenance, with elevated incidence of running issues in neglected examples. Peugeot service data indicates that a majority of drivability complaints for this engine family stem from carburettor faults or ignition system wear. Regular adjustment and using clean fuel make long-term ownership straightforward.
Analysis derived from Peugeot technical bulletins (1986-1992) and owner club maintenance logs. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PEUGEOT 170B-XN1T.
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