Three of the motors make this horrible crunching sound when I turn them by hand. But it doesn't seem to affect flight. But, I'm concern over the longeveity of the unit.
I do have the Refresh Service. So, Should I send it in or I'm just paranoid.  
Opinions and thoughts much appreciated

Thanks!

Before doing that hold the Mavic upside down and turn the motors back and forth, if you can blow a little compressed air in the top of the motor while its upside down and you are turning it.  You really should not fly with the motors in this state.

Thanks,  Ive already tried that.  Compress air and all.

Did you also try using a vacuum?

If you have a problem with motors in the air you going to fall out of the sky. I would send it in under warranty.

hridge Posted at 2017-2-2 11:44
Did you also try using a vacuum?

Yep vacuum with hose attachment while gently rotating

Put some Lube

cluc Posted at 2017-2-2 18:14
Put some Lube

Suggestions of which? I have retail triflow to specialty lubricants like Molykote.

You don't lube a contamination problem… Do you have sand between the rotor and stator… Either use an air compressor or get a can of compressed air to clean it out.  I haven't done it yet but the motor should also disassemble fairly easily, giving you the ability to separate the rotor from the stater giving it a good wipe down with some rubbing alcohol or other mild cleaner.  chances are they will do the same and charge you the $79 fee for refresh… Clean it fly it  till the pukes then send it in.