A technician is investigating a recurring failure on a hydraulic power unit.
After fixing the immediate symptom (a blown fuse), they use the '5 Whys' technique to find the root cause.
The analysis proceeds as follows: 1.
Why did the fuse blow? - The motor overloaded. 2.
Why did the motor overload? - The pump was working too hard. 3.
Why was the pump working too hard? - The fluid was too thick (viscosity too high).
What is the MOST logical fourth 'Why' question to ask in this analysis?
