Should I be concerned?

[Phantomix]

I have had my P4 for about 7 months, and I am starting to hear a quiet and strange noise when I manually turn 3 of the four motors. It is not loud, but the three motors do not feel like they are moving completely smoothly. I have heard of this sort of thing happening before, but this does not seem to be as loud as I have seen in videos. It also flies completely fine. So should I send it in, or just ignore it?

 

[Mr. Pina Colada]

The bearings are probably starting to show there wear. I don't know if DJI would do anything about it since it's not effecting flight performance. Eventually it will make a difference but if it's flying fine for right now I wouldn't worry.

 

[N017RW]

Post-flight temperature is the easiest way to check motor (bearing) 'health' relative to each other.
If flight seems normal, a motor experiencing greater load due to friction will run warmer as compared to its peers.
No special equipment is required. Your fingers will easily determine if temps differ motor to motor.
It may take a few flights to determine if any differences noted are indicative of a problem or a result of flying 'style'.

 

[Alien Warrior]

Same here, try bending the spring thingy's under the prop slightly upward. Several youtube vids on howto.
Mine is silky smooth again and I can't see why it rectifies the rumbling but it does!

Sent from my SM-G930F using PhantomPilots mobile app

 

[Brockrock]

You may want to check the video below for a possible solution - if this is what you have going on. It seem that some folks are experiencing loosening of the prop mounts and/or loosening of the prop mount springs, and this can cause a sort of 'grinding' noise. Both issues are very easy to remedy yourself, just do not over tighten those little prop mount screws...

If this is not the problem you are having, and it is the motor bearings, I suggest sending it in for repair and not flying it.