Dealer Advice?

[kamigawa120]

Hey Guys,

My Mom has a 2008 X5 si and recently just past over 50k miles,
now there is a problem with it, it makes a loud fan noise at the engine bay, both idle and on the road, my Prognosis is that there is something wrong
with the coolant or the engine thermometer or something.

I desperately need an advice from your experience,
Should i tell the Service adviser that there is either a coolant leak
(which i haven't seen yet), their might be a problem with the
engine thermometer?

Or

Should i sit tight and let them figure out what is wrong with it?

Thank you very much