Noise from an engine can be a multitude of different faults. In this case of the Toyota Corolla, a few other garages had estimated what they thought was an in internal engine failure. (Timing chain and one other garage quoted a cylinder head replacement as per valve issue.)
Not the case as we quickly discovered.
Our garage has some pretty fancy tools to get most things diagnosed, but in this case we utilized a pretty simple setup by way of the stethoscope.
Be extra cautious while using the stethoscope tip\probe when the engine is running. You can probe the backside of the water pump, as we did, and quickly identify an internal shaft\bearing defect within that component. Additionally if you have an alternator bearing on its way out, you will be able to identify a similar moan\woan\rattle type of noise.
We were grateful that we could give the client the good news, and replaced the water pump to eliminate the noise.
One last point regarding the water pump and coolant system in general. It is crucial that you stick to the guidelines of maintaining the coolant\antifreeze at regular intervals, so you don’t actually prematurely wear out coolant system parts such as the water pump.