How to Maintain the Engine of Komatsu Excavators


1. Overview

Construction machinery is always used under harsh working conditions, and the life of the engine is directly related to the quality of maintenance. Komatsu’s 80 years of experience and statistical data show that 70% of engine failures are caused by poor oil, water, and gas management.

2. The key points of engine maintenance are:

1) The person responsible for daily inspections should be responsible for strict daily inspections and correct problems immediately if any problems are found.

2) Use Komatsu pure parts for water, oil, and filter elements (diesel filter, machine filter, air filter, water filter).

3) Regular maintenance items must be implemented on time.

Before starting every day


Check the oil-water separator and drain it if there is water.


Water and debris discharged from the fuel tank


Check the air filter indicator. If it shows red, clean the air filter.


Check radiator blades and clean


Check electrical system


Check the cooling water level and add water


Check engine oil level and refill


Check engine exhaust smoke color

Before shutdown


Fill the fuel tank with fuel

First 250 hours


Replace the fuel filter element


Check the engine valve clearance and adjust it

Every 250 hours


Replace the engine oil filter and oil


Check and adjust the fan belt tension


Check the battery electrolyte levels

Every 500 hours


Replace the fuel filter

Every 1000 hours

1 Replace the cooling water anti-corrosion filter

Check turbocharger fasteners

Every 2000 hours

1 Check and adjust engine valve clearance

Clean and inspect turbocharger


Check turbocharger rotor clearance

Every 4000 hours


Check water pump


Check the fan pulley and tensioner pulley


Check shock absorbers


Note 1: Komatsu engine oil is CD grade or above, and select the corresponding viscosity grade according to the table.

Note 2: When the fuel used is of poor quality and the working conditions are severe, the engine oil should be replaced in advance.

Note 3: The replacement of cooling water depends on different antifreeze models. The inside of the cooling system should be cleaned at the same time.


Injector inspection

★The final judgment on the components should be determined after inspection and adjustment on the inspection bench.

* When performing an external inspection of the component, check the spray conditions, the action of the component plunger, and cracks in the cover or sleeve.

* If the components are defective, it will not only cause insufficient power transmission and poor exhaust, but also cause abnormal noise, vibration, and an increase in exhaust temperature. In addition, this may cause oil contamination or deterioration, and cause wear and tear on piston sleeves, etc.

★When installing, disassembling, and inspecting components, avoid damage to the tip of the component cap and the slide valve.

1. Check the spray status

1) Take out the components

2) Remove the element spring

3) Pull out the element plunger and put a small amount of fuel into the element

4) Insert the element plunger, push it in with your hands, and then spray fuel against the white paper.

Note: If sprayed on the palm of your hand, you may be injured.

5) Check the condition of the fuel injected on the paper.

★When the fuel injected from each nozzle is uniform as shown in the picture, the spray condition is good.

★If carbide is clogged on the nozzle, use a carbon cleaner to clean it.

★If you poke the nozzle with iron or other objects, the spray volume will change. So please don’t do it.

2. Inspection of plunger action

* Hold the component vertically, pull up the plunger, and then put it down to confirm whether the plunger will go down smoothly.

As a professional parts supplier with rich parts supply experience and a professional technical team, Aprilparts can provide you with one-stop construction machinery parts procurement services to ensure the normal operation of your excavators and other construction machinery.

If you want to know more about Komatsu excavator maintenance methods, you can contact us directly, this is our email: We will provide relevant services to provide you with better maintenance suggestions. Welcome to hear from you.

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