Set top box has become very noisy

[#1]

Our set top box has become very noisy. My wife originally thought it was someone in the street revving their engine. 

I tried unplugging box and restarting it. This didn't help it has recently been even louder.

Any ideas?

[#2]

As a guess:

If this is a SD/HD settop box (STB) (no recording capability) it may have a cooling fan and the bearings in the fan are starting to fail.  You would have to get another box from Verizon....

If this is a STB that is also a DVR it has a hard disk used to store your shows.  It may also have a fan... In either case the bearings in the fan or disk are starting to fail.... Once again, no choice but to have Verizon replace box....

Is there a Verizon FiOS Store (not a cell phone store) near you where you could walk in???  Before walking in call tech support and get a case started so that service center will have paperwork when you come in.

Post mfgr and model number of yout STB.