How to oil motor bearings?

[ARF]

Hi,

Does anyone oil the original motor bearings? And if so how?

I've seen conflicting info on people saying to do it and others just to leave them. The DJI dealer training told us to oil top and bottom bearings each 5hours of flight time.

 

[ARF]

Also I just noticed what looked like blue glue in the top motor cooling fins. Does anyone know what this is? I'm assuming it might be used to balance?

 

[Lesmess]

Also I just noticed what looked like blue glue in the top motor cooling fins. Does anyone know what this is? I'm assuming it might be used to balance?

I thought they were sealed for life bearings, no maintenance required?