SL500 1995 Radiator Neck Crack repair?

[Gusfazekas]

The neck on the radiator has a crack extending from the opening back towards the radiator body, also, extends past the hose connection. Anyone had success repairing this? Saw an item sold to make this repair sometime ago but I can't find the link anymore. Repair consisted of a metal sleeve epoxied into the neck. Don't know if it worked.

Also, a second problem. On top of the tank, adjacent to the filler neck, there is a plastic connector connecting the overflow hose to the overflow tank. I have leakage around that connection as well. How is this plastic connection inserted into the tank? O-Ring? Does it twist out? I don't want to break it off and I think it must have a seal underneath it. Any help with this is appreciated. Steve