Technical expansion tank repair

[sprie]

I have an issue with my overflow tank. The “nozzle” nearest the camera in the photo (the smallest) came away when I removed the hose. I have temporary stuck it back in.
I was going to buy a replacement tank, but apparently, they are no longer available, so I need to repair it.
When I started up the engine, water did soon leak from this joint, so it does need a reasonable repair.

My current plan is to get one of these:
https://rc.supplies/products/aluminium-threaded-radiator-overflow-stub?_pos=1&_sid=0598e6277&_ss=r
I am also getting the matching boss/ferule.

I was thinking I could wind the stub into the hole in the tank. I was hoping to use the boss on the inside, to use to tighten the joint, with a rubber o’ring to help seal.
But looking at the tank, the nozzle is a long way from the screw top, and there is also a baffle just inside the nozzle.

So, I am thinking:

1. I rough up the exterior surface of the tank
2. I screw the stub into the hole, with some good quality gasket sealant on the threads
3. I put some JBWeld around the exterior, in the join between the tank and the stub.

Questions:

1. Is there another/better approach?
2. I am assuming it is a pressurized system, is that correct. If so, the best I can do is keep coolant in tank just on Minimum to avoid excess pressure.

The only other thought i had was to cut a hole in the top of the tank, so i get access and can use the boss on the inside to fix the stub strongly. But then i have got to find a way to seal the hole that can withstand the pressure.

 

[the green vanper]

Hello, I'd weld the plastic. Or make it weld by someone who knows how to do it properly.

 

[Jockstrap]

Scrappy?
Later model part?
Citroen Peugeot source?

 

[Communicator]

I have an issue with my overflow tank. The “nozzle” nearest the camera in the photo (the smallest) came away when I removed the hose. I have temporary stuck it back in.
I was going to buy a replacement tank, but apparently, they are no longer available, so I need to repair it.
When I started up the engine, water did soon leak from this joint, so it does need a reasonable repair.

My current plan is to get one of these:
https://rc.supplies/products/aluminium-threaded-radiator-overflow-stub?_pos=1&_sid=0598e6277&_ss=r
I am also getting the matching boss/ferule.

I was thinking I could wind the stub into the hole in the tank. I was hoping to use the boss on the inside, to use to tighten the joint, with a rubber o’ring to help seal.
But looking at the tank, the nozzle is a long way from the screw top, and there is also a baffle just inside the nozzle.

So, I am thinking:

1. I rough up the exterior surface of the tank
2. I screw the stub into the hole, with some good quality gasket sealant on the threads
3. I put some JBWeld around the exterior, in the join between the tank and the stub.

Questions:

1. Is there another/better approach?
2. I am assuming it is a pressurized system, is that correct. If so, the best I can do is keep coolant in tank just on Minimum to avoid excess pressure.

The only other thought i had was to cut a hole in the top of the tank, so i get access and can use the boss on the inside to fix the stub strongly. But then i have got to find a way to seal the hole that can withstand the pressure.

When you compare the volume of coolant saved against total volume of cooling system, you are unlikely to reduce the pressure significantly. Also less reserve if a leak did occur. If possible plastic welding or a used part as suggested above would seem to be a better option.