This article mainly introduces how to solve the problem that the engine of Caterpillar  325C excavator

 cannot be cranked to start.

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       (1) Possible reasons. 

  1) Battery.  

2) Battery cable.  

3) Start the circuit. 

 4) Starter solenoid coil. 

 5) Start the machine. 

 6) Flywheel ring gear. 

 7) Transmission. 

 8) Engine auxiliary equipment.

  9) Hydraulic cylinder lock.  

10) Problems inside the engine.

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(2) Recommended measures. 

 1) Battery and/or battery cable.  

① Check the main power switch, battery terminal posts and battery cables for loose joints and corrosion. If there is corrosion, remove and clean the battery cables. Tighten any loose connections. 

 ② Check the battery. Charge the battery. Test the battery load. 

 2) Starter solenoid coil or starting circuit. 

 ① Check the operation of the starter solenoid coil.  

② Check the machine wiring connected to the starter solenoid coil.

  3) Start the machine. 

 ① Check the operation of the starter. 

 ② Check whether the starter pinion gear and flywheel ring gear are damaged.

4) Transmission or engine auxiliary equipment.

  ① Ensure the amount of movement of the drive train. 

 ② Make sure the timing pin is not left in the flywheel housing. 

 ③Remove and inspect any engine auxiliary equipment that may lock the engine. Auxiliary engine 

equipment that can lock up the engine include the hydraulic oil pump, air compressor, power steering

 pump, and engine oil pump driven by the rear gear set. 

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 5) Hydraulic cylinder lock. Check the fluid in the cylinder (hydraulic cylinder lockout) by removing 

each unit injector. NOTE: Drain fuel from cylinder head. When the unit injector is removed, fuel will 

flow from the cylinder head into the cylinder. 

 6) Internal engine problems.

  ① To disassemble the engine, refer to the disassembly and assembly section. 

 ② Check the internal parts for stuck, broken parts, bent parts, etc.