Fault Phenomenon: XCMG QY25K5 truck crane difficult to start in low-temperature environments; starter motor turns normally but engine fails to start.

Troubleshooting Process:
– Checked fuel level and quality: sufficient, no waxing.
– Checked glow plugs: resistance normal, preheat indicator light works.
– Checked intake system: air filter not clogged.
– Measured battery voltage during starting: voltage drops below 9V, below starting threshold.

Root Cause: The battery is aged, with insufficient cold-cranking capacity, resulting in inadequate starting torque.

Required Parts: High-capacity starter battery set.