I've pieced all my parts together for an after market coolant filter. The problem is finding the reducer tee that goes to the heater hose. What size is that hose? 1/2 5/8 or 3/4? I was thinking 5/8" but looking at it I've come across sizes 3/4" from one source which I think is right and 1/2" from another source. I need to make sure I have the correct part before I cut that hose.