Isuzu 4HK1 engine: 5.193-litre four-cylinder diesel, versions and ratings

The Isuzu 4HK1 is a four-cylinder in-line diesel engine of 5.193 litres from Isuzu Motors Limited. Isuzu’s industrial engine pages list it as the 4HK1X, turbocharged and charge-air cooled with direct injection, in versions for the Stage IIIA / Tier3 to Stage V emission classes. In Isuzu trucks it carries a suffix by version: Isuzu Philippines lists the 4HK1-TCN in its N-Series and the 4HK1-TCC and 4HK1-TCS in its F-Series, from 114 kW (155 PS) to 154 kW (210 PS), and Isuzu Australia, in an article dated 16 May 2025 on the launch of its MY25 F Series, gives the 4HK1 in TCS and TCH versions of 154 and 177 kilowatts. On this site it is the engine recorded for the Isuzu N-series in three of its versions.

Status as of 26 October 2026. Read that day: six pages of Isuzu Motors’ industrial diesel engine site (four “General Power” pages, for Stage V, Stage IV / Tier4 Final, Stage IIIB / Tier4 Interim and Stage IIIA / Tier3, and two “Generator” pages, for Tier4 Final and Stage IIIA), Isuzu Philippines’ F-Series and N-Series pages, and Isuzu Australia’s news article of 16 May 2025 on the 2025 F Series. All nine are documents of Isuzu companies. Power is given as each document prints it, in kilowatts, with metric horsepower (PS) or horsepower beside it where the document gives one; how the units relate is explained in kW, hp and Nm: how to read a truck’s power figures.

What the 4HK1 is

The industrial engine pages, published under the copyright of Isuzu Motors Limited with the heading “ISUZU INDUSTRIAL DIESEL ENGINE”, give the same base data for the 4HK1X on all six pages read. Isuzu Philippines’ truck tables add the displacement in cubic centimetres and the injection system.

Isuzu Philippines describes the engines of both its truck ranges as a “Blue Power Diesel Engine”; its F-Series table reads “4-Cylinder, Turbo-Intercooler, Common-Rail Direct Injection”. None of the Isuzu documents read names HVO, biodiesel or a gas version of the 4HK1.

The documents do not explain the letters after the family code, and the same suffix appears with different ratings. The 4HK1-TCS is listed at 154 kW (210 PS) by Isuzu Philippines and at 154 kilowatts by Isuzu Australia, while the Isuzu N-series record on this site, built from Anadolu Isuzu’s documents for Türkiye, gives the 4HK1-TCS at 140 kW and 510 Nm, the rating that Isuzu Philippines lists for its 4HK1-TCC. The engine in the photograph above is named on its Wikimedia Commons file page as a 4HK1-TCH.

Versions, emission classes and dates

Isuzu’s documents read do not number generations of the 4HK1 or give the year the engine was introduced. They show it in versions for several emission classes, for industrial use and for trucks in different markets, and only the Australian article is dated.

Industrial versions. Isuzu’s industrial pages group their engines under “General Power” and “Generator” headings, with one page for each emission class. The 4HK1X appears on all six pages, each time with 5.193L, the in-line four-cylinder OHC layout and direct injection; the “Emission Regulation” line of each 4HK1X entry repeats the class of its page.

Philippines. Isuzu Philippines’ N-Series specification table describes the engines of that range, the 4HK1-TCN among them, as “4-Cylinder, Turbo-Intercooler, Common-Rail Direct Injection Euro IV, Blue Power Diesel Engine”. Its F-Series table has an “Emission Regulation” row that reads Euro IV and Euro V in turn, and the page’s feature list names a “Euro V Compliant Blue Power Diesel Engine”; the text of the page does not say which class goes with which engine. On the Euro classes for trucks, see Euro VI (Euro 6) and Euro 7 for trucks.

Australia, 2025. Isuzu Australia’s article of 16 May 2025, on the launch of the MY25 F Series at the Brisbane Truck Show, calls the 4HK1 of its four-cylinder models new and ADR80/04 compliant, “using pPNLT standard” in its own wording, which it does not expand. It describes the engine as the latest evolution of the 4HK1 engine lineage, which “gains all new emissions control technology in 2025, with a combined Diesel Particulate Diffuser (DPD), Selective Catalytic Reduction system (SCR) using AdBlue”. How an SCR system with AdBlue works is explained in SCR and AdBlue.

Ratings as Isuzu states them

Truck versions

The Philippine figures in the table are those of the model cards for the NQR75L, FRR90M and FTR90M. Other entries on the same pages print them differently. The NQR75LS card gives “114 kW (115 PS) / 2,600 rpm” and “419 Nm (42.7 kg-m) / 1,600 rpm”. The N-Series specification table gives the 4HK1-TCN 155 PS, as the NQR75L card does, and its torque at 1,600 rpm, as the NQR75LS card does. The FRR90MS card gives “510 Nm (52.0 kg-m) / 2,600 rpm”.

Isuzu Australia says the 4HK1 “sits at the heart of this group”, meaning the four-cylinder FRR/D, FSS and FSR/D models of the 2025 F Series. Its article does not say which of these models takes the TCS and which the TCH, and it gives no torque value in newton-metres.

Industrial 4HK1X

Isuzu writes the engine speeds as “min -1”, revolutions per minute. The industrial pages give no torque figure and no date for any of the six versions.

Trucks and buses on this site with the Isuzu 4HK1

One model on this site records the 4HK1, a truck; no bus on this site records it. Its page lists the engine for the NPR 10, NPR 10 Long and NPR 3D. The figures are those of the model’s own page and of the source that page cites, in kilowatts and newton-metres as the site’s records keep them.