Is this piece needed at all? What is it's purpose? Looks like it connects to a hose for the water pump on one end and I can't see where it goes on the other end. My T connector snapped on the way to work today, so I replaced it with a coupler of the same size just to get the car working again(Pepboys was the closest shop and they don't carry T connectors with a cap). Will it be alright to just leave the coupler instead of spending another three bucks on a T connector?

 

They come in aftermarket radiator flushing kits. The factory never put anything like that in, so you should be fine without it.