I was able to find two self-service junkyards in Indianapolis (none in Bloomington) which were large enough to bother with visiting. These allow you to enter for a small fee, find the parts you want, pull them out and then pay for those parts as you leave.
U-Pull-&-Pay (map) is located north of downtown Indianapolis and has a $2 per person admission fee.
Pull-A-Part (map) is in northeast Indianapolis and also has a $2 per person admission fee.
I found a few other junkyards but they were quite small and probably not worth the trouble if you are merely wanting to be a tourist. But it's fine to go to either of these yards, pay your $2 to get in, browse around and leave without buying anything else.
I wasn't able to find anything closed or abandoned, but I wouldn't recommend doing that anyway. It's potentially dangerous and could also get you in hot water with the police for trespassing. Going to one of the above yards, you'll see an active junkyard, have paid for the right to be there, and actually meet people who use the place.