What is that square/oval metal can?

[In XS 7]

Hi guys,after I removed the low intake I notice a little square/oval shape metal can attached to the lower part of the motor(below the head block) with a rubber hose attached to it, the hose go up and connect with the upper intake, it is about 5" long and like 3" thick and maybe 2.5" wide, can you guys tell me what is it,so I can replace it if really necesary?Thank you.

[hEaT]

Oil separator for the PCV system. The PCV is farther up the hose near the valve cover.

[In XS 7]

Thank you Joe,do you know where is a good place to buy a new one?

[KhanTyranitar]

You should not need to replace it. Unless it has a hole in it, it should never need to be touched. Its the valve which is located further up in the rubber hose that needs periodic replacement. FWIW, I would stick with a genuine PCV valve, I recently bought two different aftermarket ones, and both of them would hold against vacuum, but neither would hold boost. If you sucked not eh one end, the valve would open, if you sucked not eh other it would close, but if you blew on them they would unseat and leak. And if you sucked not eh one end where it would hold vacuum then shook it like it was exposed to engine vibration, it would unseat and leak. The genuine Motorcraft ones worked flawlessly. I have used them on all my motors, and they were not significantly more than the cheaper ones. I also secured the PCV with hose clamps, just tight enough to ensure they would not leak or come loose.

[In XS 7]

Thank you very much for the info,I will stay away of that thing,it looks in a good shape,I just try to replace old parts so I don't have to worry about it for some time,but,I will leave this one alone.