Need help identifying a part in my cooling system. Detroit 8v-92TI

I have a part on my 8V-92Ti engine, serial number 8Vf130384. In a 1990 Hatteras 54' EDMY. The part is in my cooling system and started spewing coolant under pressure. I took it to a great welder in Maryland (Smittys Radiator) and he cleaned off the multiple layers of paint and said it had already been repaired with fiberglass and JBweld. No more repairs possible. It is aluminum instead of cast iron. I was told by someone that it is called an air sweep and helps regulate pressure. Have been told that it is a critical part, also told that it isn't necessary. Big clue is that on my starboard engine (same model), there isn't one. But, I am very reluctant to just run a new hose and go without the part.

The part was made by Covington and has a number on it of 89202668, but I am guessing at the last 8 in the number, it is worn away. I have the remnants of the original in the hands of a machine shop in Alabama to see what it would cost to fabricate a new one.

Any opinions or advice on...
1) the actual name of the part
2) Is it necessary
3) Where I can get a replacement without having one fabricated

The pictured elbow looks like a fitting to collect air in the cooling system with a bleed line (blue lines) going back to heat exchanger cooling tank. B
Could you show a picture of where the blue lines go. Assuming that the liquid is antifreeze mixture you could use a steel bent tube made by a shop that makes /bends tubing for vehicle exhaust lines. My best guess.

Consider joining Boat Diesel.
You can ask as a guest but a lot of info is available in their PDF files listed on the Left side of the screen. For that though you must be a member.

THey have an active D.D. EXPERT by the name of Ronald Sparks who can usually be counted on for good D.D. information, including referrals.

He is busy so he may be a bit slow to answer.

In Caterpillar speak it's called Separator-Air. Its purpose is the remove any air from the coolant as the coolant is pumped through the system.
I would hope that Detroit Diesel, not just Covington would have 2 on each 8V-92. Perhaps the Detroit part (try to get the part number) is still available, even if made by some casting shop offshore it likely would be fine as it is not a highly designed and machined part.

In the alternative, using iron pipe fittings, (a 45 & 90º, a T, a cap and some nipples) you could likely wind one together yourself after you get a new flange made and welded onto the non threaded end of the right sized pipe so it connects to the rest of the cooling system in the same manner as the original part.
The air hose fitting which I would thread through the cap on the T, might need some sealant on the threads as the cap won't be very thick. Nothing here runs at high pressure so a coolant tight assembly should be easily done. Once primed and painted it will not look Micky Mouse.

If you can source them and you have a surplus of cash you can also likely do the same thing out of aluminum fittings, but I don't know what you would gain if you keep the coolant up to spec.

As mentioned above, Boat Diesel.com is a great source for this type of information. In addition to Ron Sparks, there are other voices there who know 2-cycle Detroits. I received great advise there when I had DD's. Highly recommended.