Why doesn't it connect to anything?
and what do i do with it during a pressure test?
and if the coolant system is truly a pressurized system, why is that hose not connected to anything? Why would the coolant cap have a pressure rating if the overflow hose is always open to air?

i know on my 95 civic i don't remember but i think i have to plug the coolant overflow reservoir during pressure tests. The overflow reservoir on the 95civic is also not completely sealed so i guess it's just i don't have a great understanding of that if someone could explain the relationship between the cap and overflow opening. For example how could the reservoir possibly explode, as i have seen happen, if the overflow hose is always open to air?

 

Welcome to the forum

 

You are totally misunderstanding how the coolant resivor works.

Honestly you should not be doing a cooling system pressure check/test if you first don’t under stand of a cooling system works and the Componets that make up the cooling system.

But you could read up and learn or at least read the instructions how to use the cooling system pressure tester you are useing .

 

Im not using the pressure tester im asking a question. I don't think you understand either or you would just explain it. I do have experience. With my 95 civic i have owned for 23 years and successfully replaced the head gasket. I mean what is the point of this forum if someone asks a question and the response is basically pointing out that I asked a question?

 

I answered your question...
If you want details get a service manual..