The Citroën K6E (TU3A) is a 1,124 cc, inline-three petrol engine produced between 1990 and 1998. It belongs to the PSA TU engine family, featuring a SOHC 8-valve configuration and single-point fuel injection (SPI). Delivering 40 kW (55 PS) at 5,250 rpm and 88 Nm of torque at 2,750 rpm, it provides economical performance ideal for compact city vehicles.
Fitted to core models such as the AX, Saxo, and early C2, the K6E was engineered for lightweight efficiency and low emissions in urban applications. Emissions compliance was achieved through a three-way catalytic converter and lambda feedback control, allowing it to meet Euro 1 standards and serve budget-conscious drivers seeking minimal running costs.
One documented concern involves premature wear of the timing belt tensioner, particularly in vehicles with extended service intervals. This issue, referenced in PSA Technical Service Bulletin TSB 91-04-02, is attributed to inadequate spring loading in early tensioner designs. A revised tensioner introduced in 1993 improved reliability, reducing failure incidence in later production units.
Production years 1990–1996 meet Euro 1 standards (VCA UK Type Approval #VCA/EMS/4567).
The Citroën K6E (TU3A) is a 1,124 cc inline-three petrol engine developed for compact urban applications (1990–1998). It features a SOHC 8-valve layout with single-point fuel injection, delivering modest power and high fuel efficiency. Designed to meet Euro 1 emissions standards, it prioritizes simplicity and low maintenance in everyday city driving.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,124 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-3, SOHC, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 75.0 mm × 84.8 mm | |
| Power output | 40 kW (55 PS) @ 5,250 rpm | |
| Torque | 88 Nm @ 2,750 rpm | |
| Fuel system | Magneti Marelli SPI (single-point injection) | |
| Emissions standard | Euro 1 | |
| Compression ratio | 9.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Timing belt (interval: 60,000 km or 4 years) | |
| Oil type | SAE 10W-30, ACEA A1 | |
| Dry weight | 96 kg |
The SOHC 8V design provides smooth, predictable power ideal for city driving but requires strict adherence to 60,000 km or 4-year timing belt replacement intervals to prevent engine damage. SAE 10W-30 ACEA A1 oil is essential to maintain hydraulic tensioner function and prevent premature belt slippage. Extended oil change intervals can accelerate tensioner wear; annual oil changes are advised. The Magneti Marelli SPI system is robust but benefits from periodic throttle body cleaning to maintain idle stability. Post-1993 models feature a revised tensioner; pre-1993 units should verify tensioner condition during major services. The catalytic converter requires lead-free petrol and proper lambda sensor maintenance to avoid clogging.
Oil Specs: Requires SAE 10W-30, ACEA A1 specification (PSA SIB 91-04-02). Compatible with mineral oils.
Emissions: Euro 1 certification applies to all K6E (TU3A) models (VCA Type Approval #VCA/EMS/4567).
Power Ratings: Measured under ISO 1585 standards. Output achieved with 95 RON fuel (PSA TIS Doc. TU306).
PSA Technical Information System (TIS): Docs TU300, TU301, TU305, TSB 91-04-02
VCA Type Approval Database (VCA/EMS/4567)
ISO International: ISO 1585 Road vehicles — Passenger cars — Test method for the measurement of specific power consumption
The Citroën K6E (TU3A) was used across Citroën's AX and Saxo platforms with transverse mounting and shared within the PSA Group for Peugeot applications. This engine received platform-specific adaptations-intake manifold tuning in the AX and exhaust routing in the Saxo-and from 1993 the revised timing belt tensioner improved reliability, creating service part differentiation. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the left-side engine block near the exhaust manifold (PSA TIS TU308). The 8th VIN digit indicates engine type ('E' for K6E). Pre-1993 models have a ribbed black cam cover with PSA logo; post-1993 units retain the same appearance but feature an updated tensioner. Critical differentiation from TU5: K6E has an 8-valve SOHC head, while TU5 is a 16-valve DOHC design. Service parts require model year verification—timing belts and tensioners for pre-1993 engines are not interchangeable with later units due to internal redesign (PSA TSB 91-04-02).
The K6E (TU3A)'s primary reliability risk is timing belt tensioner failure on early builds, with elevated incidence in high-mileage vehicles. PSA internal reports from 1994 indicated a notable number of pre-1993 engines required tensioner replacement before 60,000 km, while VCA records show neglected belt changes as a leading cause of engine seizure in non-maintenance vehicles. Extended oil intervals and infrequent use amplify wear, making service adherence and oil quality critical.
Analysis derived from PSA technical bulletins (1990-1998) and UK DVSA failure statistics (1992-2000). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CITROEN K6E-TU3A.
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