My St Croix EXP is only 2 years old and at the end of the season are exhaust fan or combustion fan has started to make this vibrating loud noise. You can feel it if you put your hand on the exhaust pipe on the back of the stove. Does this sound like the motor is going or could it be just dirty? My dealer said just bring the stove down and will look at it. Like I can just pick it up and put it in my VW.