Kubota U45 noise

[Branchchipper]

Working with a friend's Kubota U45 excavator (well maintained, roughly 600 hrs);

It is making a noise for no more than 1 minute after each start-up (even when warm).
It sounds to me like a bad fan clutch bearing (rattle/squeal- noticeable, but not an OMG! sound)

When the sound suddenly goes away, you can hear what sounds like the fan engaging and moving air. So, perhaps this clutch is not freewheeling well, but is fine when it is fully engaged???

Does this thing have a fan clutch, and is that likely what I am hearing?
It is maintaining proper engine temp. and has no other operating issues.

 

[Oldtractorfixer]

Could it be a slipping fan belt that quits slipping once the battery is recharged?

 

[Branchchipper]

Don't think so... it is very regular- happens on every start, but for a short, predictable time.
No battery charging or starting problems, and the time during which it makes the noise is far too short to charge a battery.

 

[Tags]

Does it have an air conditioner? If so, it could be the clutch kicking on and off for that.