Coolant Reservoir Tank

[Waterloo]

No clue on those goofy tanks, but I would pressurize your coolant system and see if there are any leaks. Normally it is just a clamp, tighten them up every month or so, they do loosen over time. And myself, I normally replace more than a few clamps every two years, most are junk anymore. The best clamp I have found to use are these stainless steel "Breeze" clamps. They last, and do the job they are intended to do, keep the liquids and gasses in.

These are the ones I like, FleetPride sometimes has them in stock.

https://amzn.to/2Yf2NcI

And they make an assortment of sizes and styles. Worth the extra money.