In the engine compartment, usually close to the coolant regulator housing, there is the water filler neck. This serves to connect the coolant circuit for the cylinder heads. It also feeds the coolant away from the cylinder heads.
Depending on the configuration, there may be additional outlets, for venting purposes, for example, connected to the water filler neck.
Where this is required, sealing rings can be integrated, and bushes can be incorporated for attaching the water filler neck.
All the necessary leakproof and pressure checks are conducted in-process by us in-house.