bad oil leek

hi all
i just bought this car, and i noticed a oil leak, only when i start it and it looks to be coming from around the oil sending unit but not sure and there is a allen head bolt in a hole about an inch from it. anyone had this problem before, thank you all for any help
jennifer

i say next time you change the oil, take the allen bolt out, oil pressure sending unit off and reapply teflon tape on both. that should take care of it. i havent experienced it myself, most oil leaks on rages including mine, are around the valve cover gasket. i just have replaced it