Yes, you may need to replace the separator or separator system multiple times, even if it is not freeze related because of it's job and how it does it. I might add it is very good at that job, much more so than any of the GM, Chrysler or Ford systems I have seen, at a cost less performance. It is a consumable part/system however.
By the way, if you are questioning selling or keep fixing, you should probably sell. These cars require maintenance. More than a toyota or GM or whatever. They use more consumable parts to squeeze more performance out of a shorter part lifecycle. That is the philosophy, and it is a tradeoff.
I am not trying to be mean, but it
will break again. Something
will need to be replaced. You could get a car with less consumable parts, less required maintenance, and get less performance out of it. It's a choice. BMW sells you this choice normally with a warranty and the concept that in 2-3 years, you will be trading it in, or paying to keep it up. It is a different paradigm than low performance, low maintenance, 175k mile parts for everything possible. It is the same with their electronics. They work better for shorter, and give you more conveneince for a shorter period of time than an American or Japanese manufacturer would. This is my conclusion after working on this car for 3 years, and domestics for 20.
BTW I am not just telling you this and enjoying my non-broken separator. I replaced it for the second time last week, after it failed, ruptured and spewed 4 quarts of oil in 1000 miles all over my engine block.