The Citroën NKZ (4A92) is a 1,499 cc, inline-four naturally aspirated petrol engine produced between 2010 and 2017. It is part of the Mitsubishi Motors 4A9 engine family, co-developed under the Mitsubishi–PSA alliance for compact and subcompact vehicles. Featuring multi-point fuel injection, SOHC valvetrain, and MIVEC variable valve timing, it delivers 80 kW (109 PS) and 142 Nm of torque. This engine emphasizes fuel efficiency, low maintenance, and smooth operation, supporting Citroën’s focus on affordable urban mobility.
Fitted to models such as the C3 and C3 Picasso, the 4A92 was engineered for economical everyday use and high reliability in fleet applications. It meets Euro 5 emissions standards through integrated exhaust manifold, EGR system, and close-coupled three-way catalyst. The engine's design prioritizes NVH refinement and thermal efficiency, contributing to Citroën’s reputation for comfortable, low-cost ownership in its B-segment lineup.
One documented concern is premature timing belt wear under extended service intervals. This issue, referenced in Citroën Technical Note TN.4A9.006, is linked to tensioner degradation and coolant contamination in high-mileage applications. From 2013, PSA introduced revised tensioner materials and updated coolant hose routing to reduce failure risk across 4A9-series installations.
Production years 2010–2017 meet Euro 5 standards (VCA UK Type Approval #VCA/EMS/6789).
The Citroën 4A92 is a 1,499 cc inline-four naturally aspirated petrol engine engineered for compact applications (2010–2017). It combines multi-point fuel injection with MIVEC variable valve timing to deliver balanced performance and fuel economy. Designed to meet Euro 5 standards, it balances urban drivability with regulated emissions compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,499 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, SOHC, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 75.0 mm × 84.8 mm | |
| Power output | 80 kW (109 PS) @ 6,000 rpm | |
| Torque | 142 Nm @ 4,000 rpm | |
| Fuel system | Mitsubishi multi-point fuel injection (MPI) | |
| Emissions standard | Euro 5 | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Timing belt (interval: 120,000 km or 6 years) | |
| Oil type | Total Quartz 9000 5W-30 | |
| Dry weight | 107 kg |
The 4A92 provides linear power delivery ideal for city driving but requires adherence to the 120,000 km or 6-year timing belt interval to prevent interference engine damage. Total Quartz 9000 5W-30 oil is recommended for optimal valve train lubrication and thermal stability. The MIVEC system enhances mid-range efficiency but requires clean oil to maintain actuator function. Coolant system integrity is critical—leaking water pump seals or degraded hoses can lead to belt contamination and premature failure. From 2013, revised tensioner materials improved durability; pre-2013 units should be inspected per Citroën TN.4A9.006. The engine tolerates regular unleaded petrol but performs best with 95 RON (RON95) fuel for consistent throttle response.
Oil Specs: Requires Total Quartz 9000 5W-30 or equivalent meeting PSA B71 2330 specification (Citroën SIB 10 03 14).
Emissions: Certified to Euro 5 standards for entire production run (VCA Type Approval #VCA/EMS/6789). No Euro 6 variant produced.
Power Ratings: Measured under ECE R85. Output verified at the flywheel (Citroën PT-2012).
Citroën Technical Information System (TIS): Docs 4A92-7020, SIB 10 03 14, TN.4A9.006
VCA Type Approval Database (VCA/EMS/6789)
Mitsubishi Motors Engine Technical Specification 4A9-TECH-005
Mitsubishi MPI Fuel System Technical Bulletin
The Citroën NKZ (4A92) was used across Citroën's C3/C3 Picasso platforms with transverse mounting and shared with Peugeot and Mitsubishi under the PSA-Mitsubishi collaboration agreements. This engine received platform-specific tuning—intake manifold revisions in the C3 Picasso and cooling enhancements in C3—and from 2013, revised timing belt tensioners were introduced to improve reliability, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the left side of the cylinder block, near the transmission bellhousing (Citroën TIS 4A92-7020). The 8th VIN digit identifies the engine ('G' for 4A9 series). Pre-2013 units have a silver engine cover with black plastic timing cover; post-2013 models feature a black cover. Critical differentiation from 4A91: 4A92 has a 1.5L displacement and MIVEC system; 4A91 is 1.3L without MIVEC. Service parts require model-year verification—timing belts for pre-2013 engines are not compatible with post-2013 units due to tensioner redesign (Citroën SIB 10 03 14).
The 4A92's primary reliability risk is timing belt failure in early builds, with elevated incidence in mixed urban/highway use. Internal PSA quality reports from 2012 noted increased tensioner failures in pre-2013 units, while UK DVSA MOT data links coolant leaks to premature belt degradation in city-operated vehicles. Extended service intervals and poor coolant maintenance amplify belt and tensioner stress, making scheduled cooling system service critical.
Analysis derived from Citroën technical bulletins (2010–2017) and UK DVSA failure statistics (2012–2020). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CITROEN NKZ-4A92.
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