need help finding md5 salt..

[mekolat]

i am trying to find the salt used for this function:
md5($uid.$uname.$ismod.$salt)

uid is 8972
uname is mekolat
ismod is 0
salt is an unknown lowercase alnum string of 16 characters

here's the hash: 70XXe51f7XX1b7916XX25eacc3XXb317


What settings should i use to crack it?