This article introduces common faults and troubleshooting of torque converters in ZL series loaders.

 (1) Causes of excessively high torque converter oil temperature?

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① Burned transmission gear pump, excessively low or high oil level in the transmission tank, clogged oil pan filter, or clogged filter element, insufficient oil supply, resulting in insufficient fluid flow to carry away heat, thus causing excessively high oil temperature. 

② Loose engine belt, insufficient exhaust volume, slow oil heat dissipation. Or low water level in the radiator, or ruptured pipes in the engine oil cooler, resulting in insufficient coolant and slow cooling. If engine oil is mixed in the radiator, it can generally be determined that the oil cooler pipes are ruptured.

③ Since the transmission and torque converter share the same oil supply system, if the pressure of each gear in the transmission is too low (below 0.8MPa), it will cause the gear friction plates in the transmission to slip and heat up, which will also cause excessively high oil temperature. Troubleshooting methods:

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④ If 24 rollers in the overrunning clutch (two-shaft assembly) get stuck and cause mechanical friction (even though the system pressure is normal), the oil temperature will rise sharply. 。
Troubleshooting method: Replace the second shaft assembly. 

⑤ If the rotating oil seal installed on the mating surface between the inner hole of the transfer gear and the guide wheel seat is damaged, a large amount of working oil inside the torque converter will leak internally. A large amount of working oil will flow directly back to the oil pool (in the transmission) without passing through the cooling system. This phenomenon will also cause the oil temperature of the torque converter to rise sharply.
Solution: Replace the rotating oil seal. 
⑥Improper operation, such as frequently increasing the engine throttle and overloading the loader for a long time, or operating in braking conditions for an extended period, can also cause the oil temperature to rise sharply.    

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How to install the DNP engine oil pump on a 320D2 excavator

 Note: 

Keep all parts clean and free of impurities. Impurities will cause rapid wear and shorten the life of components. 

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 Note:

If any part of the engine oil pump is worn or damaged, the entire engine oil pump assembly must be 

replaced.  

 

 

 

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1. Ensure all parts of the engine oil pump are clean and free of wear or damage. For more information, see 

System Operation, Testing and Adjustment, "Engine Oil Pump - Inspection". If any part is worn or 

damaged, replace the entire engine oil pump assembly.

 

 2. If necessary, lubricate the internal parts of the engine oil pump assembly with clean engine oil. Install the outer rotor (7) into the housing of the engine oil pump (4). Note: Ensure the outer rotor is correctly installed into the housing of the engine oil pump. 

3. Install the front cover (6) into the housing of the engine oil pump (4). Note: Ensure the front cover locating pin is correctly positioned on the engine oil pump. 

 4. Install the bolts (10). 

5. Tighten the bolts to a torque of 9 N·m (80 lb in).

 

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  6. Ensure that the two locating pins (8) and (9) are correctly positioned in the housing of the engine oil pump (4). 

 

 7. Install the engine oil pump assembly onto the cylinder block. Note: Ensure that the locating pins in the engine oil pump housing are aligned with the holes in the cylinder block. 

8. Install bolt (5). Tighten the bolts to a torque of 22 N·m (195 lb in). 

9. Use tool (A) to check the backlash between the idler gear and the crankshaft gear. For more information, see the technical specifications, "Gear Assembly (Front)". 

10. Position the new (3) (not shown) onto the suction pipe (2).

 11. Position the suction pipe (2) onto the engine oil pump (4).

How to disassemble the oil pump of a 320D2 EXCAVATOR DNP engine

 Begin: 

 a. Remove the engine oil pan. See Disassembly and Assembly, "Engine Oil Pan - Removal".

Caution Keep all parts clean and free of contaminants. 

Contaminants cause rapid wear and shorten component life.

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Caution When inspecting, maintaining, testing, adjusting, and repairing products, always ensure that fluids are contained in containers. Before opening any chambers or disassembling any fluid-containing components, prepare to collect the fluid in a suitable container. 

Dispose of all fluids in accordance with local regulations and instructions. 

 

 

1. Remove bolts (2) and the suction pipe (1). 

 

 2. Remove the gasket (3) (not shown). 

 

3. Remove bolts (5). Remove the engine oil pump assembly (4) from the cylinder block.  

 

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4. If necessary, remove bolts (10) from the engine oil pump front cover assembly (6). 

 

5. Remove the front cover assembly (6) from the engine oil pump (4).  

 

6. Make temporary marks on the outer rotor (7). Remove the outer rotor (7) from the housing of the engine oil pump (4). 

 

7. Do not remove the locating pins (8) and (9) from the engine oil pump housing unless the locating pins are damaged.

 

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How to install the idler wheel on a 320D2 excavator DNP

 1. If necessary, use tool (A) to ensure piston #1 is at top dead center (TDC) of the compression stroke. For the correct procedure, see System Operation, Testing and Adjustment, "Finding Piston #1 at TDC".

 

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 2. Ensure tool (B) is installed in the bore (Y) of the cylinder block. Use tool (B) to lock the crankshaft into place.

Note: Do not use excessive force when installing tool (B). Do not use tool (B) to hold the crankshaft in place during repairs. 

 

  3. Ensure tool (C) is installed in the bore (X) of the camshaft gear (1).

 

 

 

4. Clean the idler gear (3) and inspect it for wear or damage. For more information, see the technical specifications, "Gear Assembly (Front)". Replace the idler gear if necessary.

 

5. Clean the hub (11) and inspect it for wear or damage. For more information, please refer to the technical specifications, "Gear Assembly (Front)". Replace the wheel hub if necessary.  

 

6. Lubricate the wheel hub (11) with clean engine oil. Slide the wheel hub (11) into the idler gear (3). Ensure the timing mark faces the front of the idler gear.

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7. Align the timing marks on the idler gear (3) with the camshaft gear. See Illustration 2. Install the idler gear assembly (3) and the wheel hub (11) into the recess in the timing box. Ensure the oil hole (Z) is close to the top of the wheel hub. 

 

Note: The idler gear must be tilted during installation. Ensure the holes in the wheel hub are aligned with the holes in the cylinder block. 

 

8. Clean the plate (9) and inspect it for wear or damage. Replace the plate if necessary.

 

9. Lubricate the plate (9) with clean engine oil. Align the holes in the plate (9) and the wheel hub (11). Install the plate in its original orientation. 10. Install bolt (10).

 

 11. Remove tools (B) and (C). 

 

Note: Before removing tools (B) and (C), ensure the timing marks are aligned.     

 

12. Tighten bolt (10) to a torque of 44 N·m (32 lb ft).

  

13. Use tool (D) to measure the end clearance of the camshaft gear. For more information, see Technical Specifications, "Gear Assembly (Front)". 

 

14. Use tool (D) to measure the tooth backlash between the idler gear and the camshaft gear. For more information, see Technical Specifications, "Gear Assembly (Front)". 

 

15. Use tool (D) to measure the tooth backlash between the idler gear and the crankshaft gear. For more information, please refer to the technical specifications. "Gear Assembly (Front) 5

 

 16. Install the new O-ring (4) onto the plug (5). Install the plug (5) onto the cylinder block. Tighten the plug (5) to a torque of 21 N·m (186 lb in). 

 

 17. Lightly lubricate all gears with clean engine oil. End: a. Install the fuel injection pump gear. Please

 refer to Disassembly and Assembly, "Fuel Pump Gear - Installation". b. Adjust the engine valve clearance. Please refer to System Operation, Testing and Adjustment, "Engine Valve Clearance - Inspection/Adjustment" for the correct procedure.

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How to disassemble the idler gear of 320D2 EXCAVATOR DNP?

                                                                Disassembly steps

  Begin:

a. Remove the fuel injection pump gear. See Disassembly and Assembly, "Fuel Pump Gear - Removal". 

 b. Remove the valve cover. See Disassembly and Assembly, "Valve Cover - Removal and Installation". 

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Note: Either of the two tools (A) can be used. Please use the tool most suitable for you. 

 

 Note: Care must be taken to ensure that the fuel pump timing is not altered during the removal of the fuel pump gear. Carefully follow these steps to remove the fuel pump gear.

 

Note: 

Keep all parts clean and free of impurities. Impurities will cause rapid wear and shorten the lifespan of parts.

 

 

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 1. Remove the plug (5) from the cylinder block. Remove the O-ring (4) from the plug (5). 

 

 2. Using tool (A), rotate the crankshaft until piston #1 is at top dead center (TDC) of its compression stroke. Refer to System Operation, Testing and Adjustment, "Finding Piston #1 at TDC". 

 

 3. Install tool (B) into the bore (Y) of the cylinder block. Use tool (B) to lock the crankshaft in place. Note: Do not use excessive force when installing tool (B). Do not use tool (B) to hold the crankshaft in place during repairs. 

 

4. Ensure tool (C) is installed in the bore (X) of the camshaft gear. Use tool (C) to lock the camshaft in place. 

 

 5. Ensure gears (1), (2), and (3) are marked to indicate alignment.

 

 6. Loosen the nuts (7) on all rocker arms (8). Loosen the adjusters (6) on all rocker arms (8) until all valves are fully closed. Note: Failure to fully loosen all adjusters may result in valves contacting the piston.

                             

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 7. Mark the plate (9) to indicate the orientation. Note: Identifying the markings ensures the plate is installed in its original alignment position. 

 8. Remove the bolts (10). 

9. Remove the plate (9). 

 10. Remove the idler gear assembly (3) and the hub (11) from the recess in the front housing. Note: The idler gear must be tilted during disassembly. 

11. Remove the hub (11) from the idler gear (3).

 

How to troubleshoot uncontrolled heat in the cab of a Caterpillar 311B Hydraulic Excavator.

  

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Possible Cause： 

 1 The water valve is installed incorrectly or backwards.

 

 a water valve control, inspect the water valve to ensure it is installed correctly. 

2. Some water valves have

 

 an arrow on the side of the valve body indicating the direction of water flow. Make sure the arrow points 

 

toward the line leading to the heating coil. 

3. If the machine is equipped with a cable-operated water valve,

 

 ensure the cable is not wrapped around the valve or the frame. 

 4. If the machine is equipped with an 

 

electric water valve, ensure the actuator is securely connected to the valve.

 

 

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 Possible Cause 2 

 There is an electrical problem with the control panel. 

 1. Check the control panel to 

 

ensure that power is supplied to the control panel after the machine is started. 

 2. Check that the wiring 

 

harness is connected to the control panel. 

 3. Inspect the wiring harness for any damage or exposed wires.

 

  4. Check the circuit breaker or fuse to ensure that there is no open circuit in the system.

 

 

Possible Cause 3 

The water valve cable or potentiometer is faulty. 

 1. Determine the type of water valve 

 

control used on the machine. 

2. If the water valve has a cable connected, proceed to step 3. If the machine

 

 has a built-in potentiometer, proceed to step 5. 

3. Verify that the cable is connected to the water valve 

 

handle. 

4. Check the water valve to ensure that the water valve is fully open when the temperature control

 

 knob is set to the hottest position. 

5. Verify that the potentiometer is connected to the wiring harness in 

 

the cab instrument panel. 

6. Check the water valve to ensure that the water valve is fully open when the 

 

temperature control knob is set to the hottest position.

 

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Caterpillar 311b excavator Heating System Troubleshooting part 1

 Symptom: When the heater control knob is turned to the hottest position, there is little or no heat flow to the cab.

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 The following problem-solving information is intended for locating and correcting problems in heating systems. Different problems may cause the same or similar system conditions (symptoms). Refer to Testing and Adjusting, SENR 5664, "Heater Performance - Tests" to evaluate system performance before beginning the corrective procedures. The problem must be diagnosed first. If any parts are found damaged during inspection, repair or replace them.

 Symptom: When the heater control knob is turned to the highest setting, little or no heat flows to the cab. Possible Cause 1 The blower motor is not operating. 1. Check the circuit breaker or fuse box to ensure there are no open circuits in the system. 2. Visually inspect the wiring harness for damaged wires and missing connectors. Refer to the electrical schematic for each machine to ensure proper connections. 3. Inspect the fan blades to ensure they are not obstructed or stuck. 4. Check that the fan switch operates properly at all settings. The blower motor should operate at a variety of settings and temperatures.

Possible Cause 2 There is a leak in the system. 1. Check the hose clamps to ensure they are not missing and are tightened according to the torque values ​​shown in the diagram. 2. Check the heating coil for any visible cracks or leaks. 3. Check the water valve to ensure it is installed correctly and is functioning properly.

Possible Cause 3 The engine cooling system's inlet/outlet is closed. 1. Check the valve connecting the heater hose to the engine block. 2. Ensure the valve is fully open.

Possible Cause 4 The hoses connecting the system are kinked or clogged. 1. Check the hoses for blockages or bends. Blockages and bends in the heater hoses can restrict the flow of coolant and reduce the performance of the entire heating system. 2. Replace any hoses that may be restricting coolant flow.

Possible Cause 5 The heater's controls are malfunctioning. 1. Determine the type of controls used on the machine. 2. If the system is equipped with a water valve, proceed to step 3. If the system is equipped with a blend door, proceed to step 6. 3. Inspect the water valve for signs of damage. 4. Inspect the water valve to ensure that it fully opens when the temperature control knob is set to the hottest position. 5. If the water valve will not open or close, proceed to "Possible Cause 6." 6. Inspect the blend door. 7. Inspect the blend door for any damage. 8. Ensure that the insulation on the blend door is intact. 9. Ensure that the actuator is connected to the blend door. 10. Inspect the blend door to ensure that it fully opens when the temperature control knob is set to the hottest position.

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 Possible Cause 6 The water valve cable or potentiometer is faulty. 1. Determine the type of water valve control used on the machine. 2. If the water valve has a cable connected, proceed to step 3. If the machine has a built-in potentiometer, proceed to step 5. 3. Inspect the machine to ensure that the cable is connected to the water valve handle. 4. Inspect the water valve to ensure that the water valve is fully open when the temperature control knob is set to the hottest position. 5. Inspect the machine to ensure that the potentiometer is connected to the wiring harness in the cab instrument panel. 6. Inspect the water valve to ensure that the water valve is fully open when the temperature control knob is set to the hottest position.

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