Okay, here's the story, I just turned 16 and i'm getting my liscense in about 2 weeks, I've been looking for a car.. I was hoping for a while that I'll get my moms 97 avalon xls, but she wants to keep that instead of give it to me

. About a month ago i started to look at this black 96 avalon that seemed to be abandoned.. i was walking home one day and the owners were driving it up and down the driveway, so i stopped and asked them if its for sale, and some info about it. 96 black avalon xl, cloth bucket seats.. and so on, i sort of new what to expect from an avalon since we've owned one for like 7-8 years now. When i opened the hood there was this big empty spot by the antifreeze or something.. i couldn't figure it out i knew something went there, but i couldn't picture our avalon.. i took a picture of the engine.. i went back home and opened the hood on mine and i saw what was missing, but idk what it is? heres a pic. my parents like this alot because we already own one avalon and its a good 1st car.
oh ya, it has about 160-165k miles and the guy was asking like 3k but i know im not paying that much lol. if that thing missing is nothing serious maybe 2300 offer or so. i just have to know what that is!! help please?