Strange Noise in a 200 Jeep Cherokee


Just recently been hearing a loud rumbling that sounds like a fan turning on and off. Never heard it before, and you can feel it through the whole front of the car. Car operates fine, but every once in a while, this whatever it is turns on and rumbles - Been to two shops and they couldn’t find a thing but I know what I hear when I hear it - and I have Ear-Witnesses!

Any ideas??