Description

Komatsu 3.1522, 3.1524, T3.1524 Workshop Manual

I’ve seen too many guys in my shop waste half a day because they relied on some aftermarket PDF that had the ring end gap wrong or skipped the torque angle on a cylinder head bolt. That’s not how we work here. If you’re holding a Komatsu 3.1522, 3.1524, or T3.1524 – and you want the job done once, without comebacks – you need the factory Workshop Manual. This is the exact document Perkins Engines put together in 1984, still current for these industrial diesels. 98 pages, no guessing, no aftermarket rewrites.

Cylinder Head and Torque Sequences

Section C of this manual takes you through removing and refitting the cylinder head. You get the tightening sequence drawn out, step by step. I’ve torqued more head bolts than most people have had hot meals – and I still check every sequence against factory specs. The manual tells you the order, the torque in ft-lb, and the angle if any. Don’t skip the gasket surface cleaning note in the foreword. Page 4 says it plain: clean off joint faces, remove burrs. That’s not optional.

Crankshaft and Main Bearings: Factory Clearance Specs

Section F on crankshaft and main bearings gives you the wear limits and bearing clearances in imperial units. You need to plastigauge the mains? The manual tells you the acceptable range. No generic numbers. If you’ve got a 3.1524 that’s knocking, you’ll want to check the crankshaft end float spec here. The oil clearance data is per bearing journal. I’ve had guys bring me engines they rebuilt using a Chilton’s spec – they were 0.002” off. That’s a spun bearing waiting to happen. Use the real data.

Does the Fuel Section Cover Injection Timing?

Section L – Fuel System – covers the injection pump, injectors, and timing. Yes, it gives you the static timing procedure. The manual assumes you know to blank off open ports on precision components (page 4 foreword again). If you’re working on the T3.1524 with the turbocharger, fuel delivery rates are different. The manual lists the pump settings for each variant. Don’t assume the 3.1522 and 3.1524 use the same injection timing – they don’t. Check the data table at the start of Section L.

Cooling System: Thermostat and Pump Data

Section K covers the cooling system. Thermostat opening temperature, water pump disassembly, and coolant capacities. Overheating a Komatsu diesel because you put in the wrong thermostat is a rookie mistake. This manual gives you the exact temperature range. Also includes the torque for the water pump bolts – it’s in ft-lb, not some made-up number. If you’re replacing the cooling system, you’ll need the hose dimensions listed too. No guesswork.

Turbocharger Disassembly (T3.1524 Only)

Not all three models have a turbo. The T3.1524 does. Section T goes through turbocharger inspection, cleaning, and reassembly. You get the shaft clearance specs and the torque for the turbine housing bolts. I’ve seen a lot of cheap rebuilds fail because the wastegate actuator was set wrong – the manual shows the rod length adjustment. If you don’t have this section, you’re flying blind.

Who Needs This Manual?

Home garage guys who want to rebuild their own Komatsu engine without turning it into a boat anchor. Professional mechanics who bill by the hour and can’t afford to guess a torque spec. Equipment owners who maintain their own excavators or generators. If you’ve got a 3.1522 in a compressor or a 3.1524 in a generator set, this manual covers all the maintenance in Section B as well – oil change intervals, filter specs, fan belt tension. The audience is anyone who respects a factory spec.

Why OEM Beats Aftermarket

Aftermarket manuals copy the data but often introduce errors. I’ve seen a “compatible” manual list the wrong main bearing torque for a 3.1522 – it was off by 15 ft-lb. That’s a cracked block waiting to happen. This document is scanned from the original Perkins publication. The page layout, the diagrams, the torque tables – they’re untouched. You get the same information my technicians use when they rebuild these engines. No third-party reinterpretation. Period.

Frequently Asked Questions

Does this manual cover the T3.1524 turbo model?

Yes. Section T is specifically for the T3.1524. It includes turbo disassembly, clearance checks, and reassembly torque values.

Can I use this for the 3.1522 and 3.1524 interchangeably?

Most procedures are common, but injection timing and turbo-related steps differ. The manual clearly separates data for each model in the technical data section (Section A).

What about wiring diagrams?

This workshop manual focuses on the engine mechanicals – cylinder head, block, fuel, cooling, etc. It does not include full electrical wiring for equipment, but it does cover the alternator and starter motor (Section N). For vehicle wiring, you’d need a separate chassis manual.

Are the torque specs in imperial or metric?

All torque specs in this manual are given in imperial foot-pounds (ft-lb). The data was originally produced for the North American market. You will not find Newton-meters unless you convert them yourself.

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If you’re working on any of these Komatsu diesels, you need the actual factory data. Stop relying on forum threads and copied PDFs. Access the Factory Manual and get the specs that Perkins and Komatsu certified. Your engine will thank you.