Leaking Oil Subaru Impreza 07

my car is leaking oil it seems to be coming from this part on the back of the engine on the passenger side. It appears to be missing some kind of bolt, but I would like to know what this part is/does before I mess with it

Subaru’s don’t leak oil – they mark their territory. Try the Ultimate Subaru Message Board (USMB.ORG) They help I’ve received from them has kept my 'roos running well past 250K miles each.

Ignore the missing bolt. Engines often have various threaded holes that end up unused on a final assembly. They generally are there to attach a bracket for the assembly line, a lifting hook, or some item that would bolt there if you got soem specific accessory. Sometimes ther’re leftover from an earlier version of the engine, made unnecessary due to some design change.

Don’t mess with it. Next oil change have the mechanic put it on a lift and investigate properly. One can go crazy trying to track down an oil leak just crawling underneath with a flash light.

Does it appear to leak from where it meets the transmission’s bell housing? Or is it leaking from the head?

Be sure to keep an eye on the oil level on the engine oil dipstick. Every time you fill with gas, until you get an idea how much oil you are loosing.

I don’t have experience w/you make/model. But in my experience with econo-boxes, the most likely place for an oil leak to start is the valve cover gaskets. These are usually fairly inexpensive to replace. Ask your mechanic to inspect them for leaks. Sometimes all that needs to be done is tighten a few bolts on the valve cover. But don’t do this yourself, as the bolt torque specs have to be adhered to, otherwise you can easily make a simple to fix problem into a difficult to fix problem.