I've run my MMM in snow and due to my laziness of not fully sealing the chassis a bunch of it collected between the motor bullets. All was fine and I ran in the snow again a few days later with more protection and the esc rotated degrees.
Check out my custom converted 8ight:
Sub 7lb, lowest CG of any 1/8 buggy
So whats the real anwser on this? i would love to cover the motor and esc and run in the snow but obviously something is gonna get wet eventually . So short of totall submersion is it ok ??? I wonder if water in the motor would make the esc go nuts trying to read the position?
i have run through puddles to the point it starts sputtering. i have one body that has a hole cut in the windshield and one that doesn't. i recommend using a hole when its warm outside and you need some cooling over the motor esc and batts. When its wet keep things from soaking the inside.
All that said i have sprayed off the ESC and motors many times after some very muddy runs on the track then cleaned it up immediately with the air gun and have had no troubles whatsoever.
If you dont submerge and keep a body on the truck and you blow it out then finish with some wd-40 to drive out the remaining moisture things will be fine.