This article is writing maintenance instruction manual of komatsu excavator, for mini and heavy exavators.

1.  Check before starting komatsu engine

   1.1 Check coolant level and add water1.2 Open the door behind the left side of the machine and check that the water level of the cooling water should be between the “full” and “low” marks of the radiator auxiliary tank.If the water level is too low, water should be added to the “full” position through the filling port of the auxiliary water tank.1.3 Tighten the cover after adding water

   1.3 Tighten the cover after adding water

1.4 If the secondary water tank is empty, check the water leakage first, and then fill the radiator and secondary water tank with water. 

2. Check the oil level in the engine oil sump and refuel

2.1 Open komatsu engine
2.2 Remove the dipstick and wipe the oil with a cloth
2.3 Insert all the dipstick into the nozzle tube before pulling it out
2.4 The oil level should be between the H and L marks on the oil gauge

2.5 If the oil level is lower than L mark, oil should be added through the refueling port

2.6 If the oil level exceeds the H mark, drain the excess oil through the drain plug and check the oil level again.
2.7 If the oil level is correct, tighten the filler cap and close the engine hood
2.8 When checking oil levels after engine operation, wait at least 15 minutes after komatsu engine shutdown before checking
2.9 If komatsu excavator is tilted, it should be level before inspection

3. Check fuel level and refuel 

3.1 Check that the tank is full through the observation window in front of the fuel tank.
3.2 After the cap of the refueling port is opened, the floating rod reflecting the oil amount will rise. Please check whether the fuel is filled up. When checking, please use both visual measurement and floating rod.

3.3 If the tank is not full, fill through the nozzle until the float gauge is raised to its maximum position. Fuel capacity: 340 litres.
3.4 Position of the top of the float ruler when the tank is full: about 130mm from the top of the fuel tank.

3.5 After refueling, push the float ruler straight down with the refueling cap.Be careful that the float rule is not clamped by the seal of the filler cap, and tighten the filler cap securely.

3.6 If the vent hole in the top cover is blocked, the pressure in the tank will drop and the fuel will not flow.Always clean the hole.
4. Check the oil level in the hydraulic tank and refuel
4.1 If the working device is not in a flat position, start the engine and allow the engine to run at a low idle speed, retract the bucket rod and bucket cylinder, then lower the arm so that the bucket teeth contact the ground, and finally shut down the engine.

4.2  After the engine has been shut down for fifteen seconds, each joystick (working device and walking joystick) is moved in all directions at full stroke to remove internal pressure.
4.3 Open the door on the right side of the machine and check the observation window.If the oil level is between the H and L marks, the oil level is normal, Do not add more fuel than the H mark, which will damage the hydraulic circuit and cause the oil to shoot out, If the oil level is below the L mark, open the top cover of the hydraulic tank and refuel through the refueling port.

4.4 The oil level varies according to the oil temperature. Check against the following benchmarks: Before work: near the L mark ( oil temperature is 10℃~30 ℃ ) Under normal operation: H mark nearby ( oil temperature between 50℃ and 80 ℃ ).
5. Check the air filter for clogging
5.1 If the monitor flashes, clean or replace the filter element immediately.
5.2Clean and replace the outer filter element, Remove the outer filter element and clean the inner side of the air filter shell and cover plate, Blow dry compressed air (7kg/cm ^ 2) directly from the inside of the filter element along the creases, The filter element is then blown on the outside along the fold and then on the inside Each time the outer element is cleaned, remove the label from the outer element.

5.3 Replace the outer filter which has been cleaned 6 times or used for more than one year, and replace the inner filter.
5.4 If the newly cleaned outer filter element is installed soon, the monitoring light flashes. Even if it has not been cleaned 6 times, the inner and outer filter elements should be replaced at the same time. Check whether the inner filter element installation nut is loose. If it is loose, it should be tightened. After cleaning, when inspecting with a light bulb, replace the filter element if holes or rarefied parts are found.
5.5 Note: Do not use pleated or sealed elements that have been damaged, and do not knock with anything when cleaning the elements. Install clean filter element and fix with butterfly nut. If gasket or butterfly nut breaks, replace with a new one. Remove the exhaust valve and blow it clean with compressed air.Install after cleaning.
5.6 Replace the internal filter element. Remove the inner filter element, Install the new inner filter to the interface and tighten it with the nut.The inner filter element cannot be cleaned and reinstalled.

6.Check electrical wiring

6.1 Check the fuse for damage, the circuit for signs of short circuit or break, and the terminals for looseness.

6.2 Check the circuit of battery, starter motor and alternator.

6.3 Check the accumulator of inflammables around the battery.

7 . Check water and sediment in oil-water separator

7.1 The oil-water separator separates water mixed in the oil.If the buoy reaches or exceeds the red line, release water according to the following method: loosen the release screw plug and release the accumulated water until the buoy reaches the bottom, tighten the release screw plug.