Description

Isuzu 4JG2, 4JG1 Parts Catalog – 364 Pages of Factory Part Numbers

I’ve been wrenching on Isuzu diesels for twenty-eight years, and the first thing I tell any junior tech who walks into my shop is: Isuzu 4JG2, 4JG1 Parts Catalog is the only way to order parts without getting burned. Aftermarket catalogs get the part numbers wrong, leave out superseded revisions, and waste your time. This OEM catalog – 364 pages, printed from the factory data – gives you the exact figure numbers, exploded views, and numerical indexes you need to find the right bolt, gasket, or injector line. No guessing. No returns.

You know the drill: you pull the cylinder head cover on a 4JG2, find a cracked rocker shaft bracket, and the aftermarket parts site says, “Fits all models.” That’s a lie. The factory catalog lists parts by engine model, production month, and ID plate code. Spend the extra ten minutes cross-referencing here, and you won’t send a customer home with the wrong part. That’s what this thing is built for.

What This Parts Catalog Actually Covers

This is the Parts Catalog for the Isuzu 4JG1 and 4JG2 diesel engines, covering model years 1993 through 2007. It includes the Engine Models Table (page P-4), the ID Plate interpretation guide (page P-10), and the full Illustration and Text section spanning 286 pages of exploded diagrams. The Numerical Index (19 pages) lets you look up a part number and find the exact figure and key. The Alphabetical Index (14 pages) works in English and Japanese – handy if you’re dealing with JDM engines.

Using the ID Plate to Find the Right Parts

Every Isuzu engine has an ID plate stamped with the engine model name and production month/year. The catalog shows you exactly how to read that plate (page P-10) and then match it to the Engine Models Table. For example, a 4JG2 built in March 2000 uses a different oil pan gasket than a 1995 build. The catalog lists supercessions – you’ll see the updated part number right in the table. Don’t skip this step. I’ve seen guys order a whole cylinder block because they misread the ID plate.

3 Ways to Navigate the 364 Pages

First, use the Figure Number Index – three pages that list every figure title from “PARTIAL ENGINE” to “OIL PAN AND LEVEL GAUGE.” Find the figure number (e.g., 0-10 for cylinder head cover), flip to the illustration, and note the key number. Second, use the Alphabetical Index – look up “cylinder head” and get the figure number. Third, use the Numerical Index if you have a known part number and need to verify it fits your engine. All three indexes are in the front of the catalog, so you don’t flip through 286 pages blind.

Why Factory Parts Catalog Beats Aftermarket

Aftermarket catalogs often combine multiple engine families into one generic list. That’s fine for a rough idea, but when you need a specific injector nozzle for a 4JG1 with a “TPG” ID plate code, the aftermarket data won’t show the three different nozzle options based on production date. This factory catalog gives you the exact part number, the superseded part number, and the figure location. I’ve seen a 4JG2 owner order a head gasket from an aftermarket site that was 0.5 mm too thick – caused a compression leak. The factory catalog lists the correct gasket thickness by engine serial number range.

If you’re working on a 4JG2 or 4JG1, you also need the service manual for torque specs and procedures. Check out the Isuzu 4JG2 Diesel Engine Service Manual”>Isuzu 4JG2 Diesel Engine Service Manual – that’s the other half of the puzzle. For a broader set of Isuzu diesel engine manuals, the Isuzu 4JB1 4JG2 4JH1-TC 4HF1 4HE1-TC Service Manual PDF”>Isuzu 4JB1 4JG2 4JH1-TC 4HF1 4HE1-TC Service Manual covers multiple families. And if you’re working on the excavator side, the Isuzu ZX240-3 Series Parts Catalog – 370 Pages OEM”>Isuzu ZX240-3 Series Parts Catalog is another 370-page OEM reference.

Who Needs This Parts Catalog

If you’re a home garage mechanic rebuilding a 4JG2 from a NPR truck, this catalog saves you from ordering the wrong oil pump. If you’re a shop owner with a fleet of Isuzu diesel forklifts, the Abbreviation List (page P-18) decodes all the Japanese acronyms on the diagrams. Beginners: don’t buy this if you expect step-by-step repair instructions. This is a parts catalog – it tells you what part number to order, not how to install it. Pair it with a factory service manual, and you’re set. For a background on the evolution of diesel engine documentation, see this Automotive Industry Overview”>Automotive Industry Overview.

One more thing: the electrical illustrations in the back reference the battery and starter circuit. If you’re tracking down a no-start on a 4JG1, the part numbers for the starter relay and battery cables are in the Illustration and Text section. Check the Automotive Battery”>Automotive Battery page for general battery specs, but the catalog gives you the exact Isuzu part number.

Frequently Asked Questions

Does this catalog cover both the 4JG1 and 4JG2 engines?

Yes. The Engine Models Table lists both engines with their ID plate codes.

How do I find the exact part number for my engine?

Start by locating the ID plate on your engine. Write down the engine model name (e.g., 4JG2) and the production month/year. Then turn to page P-4 of the catalog – the Engine Models Table – and find the row that matches your model and date range. That row gives you the figure number for the main assembly. From there, look up the figure in the Illustration and Text section, note the key number, and read the part number from the adjacent text. If the part number has been superseded, the catalog will show the updated number next to the original. This whole process is described in detail on pages P-2 through P-5 under “How to search for the Part Number.”

Can I use this catalog for other Isuzu diesel engines like the 4BC2 or 4HF1?

No. This catalog is specific to the 4JG1 and 4JG2 engines. Other Isuzu engines have different part numbers and figure indexes.

What year ranges are included?

1993 through 2007, as stated on the cover.

You’ve got the factory part numbers, the indexes, and the diagrams. Quit wasting time on aftermarket parts lookups. Access the Factory Manual now and get the right Isuzu parts the first time.