1992 Golf "oil separator(?)"

A mechanic told me that i was going to need a new "oil separator"..

Its not a high-performance car. Its a work-car.

He quoted me about $300 for the job.

I cannot seem to find the part online, except under high-performance
stuff.

Do i really need to do this?

does he mean an oil filter? oil filter seperates dirty oil from clean oil. put dirty oil in and cleaner oil comes out.

What engine? Did he show you the part? Is he referring to the baffle on the top of the valve cover? What is the problem that you brought it to him for?

What engine? Did he show you the part? Is he referring to the baffle on the top of the valve cover? What is the problem that you brought it to him for?

Its a 92 Golf GL 1.8.
I took the car in because it hadnt been starting without starter fluid.
No, he did not show me the part.
He replaced a vacuum hose and an 'oil separator grommet', but told me
that it would be good to replace the oil separator.

I'm not sure WHAT he is referring to.

He's referring to the round plastic device on top of the valve cover. As long as the rubber & plastic hose that goes to it is intact back to the engine block it should be fine. I'd look for the problem elsewhere, start with the basics like fuel & air filters.