This setup has been bugging me. I deleted everything behind the driver's heater and needed to close the loop. Thought I had it figured out with these elbows but I am losing sleep over it... one side I think is 1/2 " and the other is 3/4".... I think.... I used some landscaping elbows but I now know there heat rating is only up to 110°F that wont cut it. Can I see your set up for closing and looping the system back? I saw some galvanized threaded elbows in someone's build. CE 200 2004 8 window international.