Refrigator/Freezer

Hi all,
My wife purchased this used refrigerator and now it makes this sound "kitchen-aid" of something kinda grinding, it has a fan guard on it towards the back and it seems like it comes from that area where the fan is...now its under warranty till march, and I want it fix.. The hard part of this is it only makes the sound every so often.. repair guy says it was the ice maker..i been trying to notice when it makes this noise what position the ice bar is in. The other day it was in the up position(off) due to ice and it was going off like mad and I felt that fan cover and it felt like it was coming from there. when I felt it with my hand it even seem like it slowed down due to the noise. The repair guy changed out the ice maker and still making it..does it have something to do with this ice maker when its in the up position. or is it really the fan that's

doing it? can someone tell me to ask the repair guy to check?

Thanks for your guys help