I have an old radiator with a broken regulator, the heat over the years has weakened it and it started to suck in air. As a temporary fix until the radiator is replaced, a clamp was designed to cover it and prevent leaks to increase. The original regulator was wrapped in thread seal tape and the PLA clamp placed on top, tightened with 2 machine screws & nuts,

The original regulator had an outer diameter of 44 mm. the clamp depth is 20mm and on the outer end there is a rim with inner diameter 40mm. The screw holes are 4.3 mm in diameter.