The Isuzu 4JK1 is a 2,499 cc, inline‑four turbo‑diesel engine produced since 2012. It features a double overhead camshaft (DOHC), 16-valve configuration with common-rail direct injection and a variable geometry turbocharger (VGT), delivering a balance of power and efficiency for modern commercial vehicles. Peak power is rated at 110 kW (150 PS) with 350 Nm of torque, designed for strong low-end pulling power and sustained highway cruising.
Fitted primarily to the Isuzu D-Max pickup and MU-X SUV, the 4JK1 was engineered for global markets requiring robust performance, durability, and compliance with stringent emissions regulations. Emissions compliance is achieved through a diesel particulate filter (DPF) and exhaust gas recirculation (EGR), meeting Euro 5 standards and later updates for Euro 6 in specific markets.
One documented concern is potential carbon buildup in the EGR system leading to reduced performance, as noted in Isuzu Service Information Bulletin SIB-2015-03. This is often linked to frequent short-trip driving cycles that prevent the DPF from completing passive regeneration. Software updates and revised EGR coolers were introduced to mitigate this.
Isuzu
All production years (2012–Present) meet Euro 5 standards; 2017–Present models meet Euro 6b/c in applicable markets (VCA UK Type Approval #VCA/EMS/7654).
The Isuzu 4JK1 is a 2,499 cc inline‑four turbo‑diesel engineered for pickup and SUV applications (2012-Present). It combines DOHC 16-valve architecture with common-rail injection and a VGT to deliver strong, linear torque and improved refinement over its predecessor. Designed to meet Euro 5 and Euro 6 emissions standards, it prioritizes durability and low running costs for professional users.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,499 cc | |
| Fuel type | Diesel | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 92.0 mm × 94.0 mm | |
| Power output | 110 kW (150 PS) @ 3,600 rpm | |
| Torque | 350 Nm @ 1,800–2,800 rpm | |
| Fuel system | Common-rail direct injection (Denso) | |
| Emissions standard | Euro 5 (2012–2016); Euro 6b/c (2017–Present) | |
| Compression ratio | 16.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Variable Geometry Turbo (VGT) | |
| Timing system | Chain-driven DOHC | |
| Oil type | API CJ-4/CK-4, SAE 5W-30 | |
| Dry weight | N/A |
The DOHC design and VGT provide a broad, flat torque curve ideal for towing and off-road use but require strict adherence to 10,000 km oil changes with low-ash (CJ-4/CK-4) oil to protect the DPF and turbocharger. The timing chain is designed for life but should be inspected for noise after 200,000 km. EGR system clogging (SIB-2015-03) is a known risk with urban driving; regular highway runs are recommended to facilitate DPF regeneration. Fuel quality is critical; contaminated fuel can damage the high-pressure common-rail injectors.
Oil Specs: Requires API CJ-4 or CK-4 low-ash specification oil to protect the DPF (Isuzu Owner's Manual 2015). ACEA C3 is an acceptable alternative.
Emissions: Euro 5 certification applies to 2012-2016 models; Euro 6b/c applies to 2017+ models in applicable markets (VCA Type Approval #VCA/EMS/7654).
Power Ratings: Measured under ISO 1585 standards. Power and torque figures are consistent across global markets for this specification (Isuzu TIS Doc. 4JK1-SPEC-01).
Isuzu Technical Information System (TIS): Docs 4JK1-SPEC-01, SIB SIB-2015-03
VCA Type Approval Database (VCA/EMS/7654)
ISO 1585 Engine Power Measurement Standards
The Isuzu 4JK1 – Diesel was developed for Isuzu's D-Max and MU-X platforms with longitudinal mounting. This engine is not shared with other manufacturers and features platform-specific calibrations for the D-Max pickup and MU-X SUV. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the flat machined boss on the front left side of the cylinder block, near the alternator (Isuzu TIS 4JK1-ID-01). The 8th VIN digit for Isuzu D-Max is 'K' for this engine. Visually, it is identifiable by its DOHC valve cover, centrally mounted common-rail fuel rail, and the VGT turbocharger on the exhaust manifold. Service parts like the cylinder head, block, and crankshaft are fully interchangeable between D-Max and MU-X applications of the same model year. ECU and emissions components may differ between model years due to Euro 5 to Euro 6 updates.
The 4JK1's primary reliability focus is on the EGR and DPF systems, particularly for vehicles used predominantly in urban environments. Isuzu internal data indicates a higher service rate for EGR cleaning in fleet vehicles with short duty cycles, while UK DVSA MOT statistics show emissions system faults as a common failure point for high-mileage examples. Regular highway driving is the single most effective preventative measure.
Analysis derived from Isuzu technical bulletins (2012-2024) and UK DVSA failure statistics (2020-2024). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about ISUZU 4JK1.
Comprehensive technical documentation and regulatory references
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ISUZU Official Site
Owner literature, service manuals, technical releases, and plant documentation.
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
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GOV.UK: Vehicle Approval
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