you can measure the barb it came off of maybe? it might be some weird metric size too, I think I used 1/4 inch? its been a while so I really don't remember....
I have a trail tech speedo to install and needed the radiator hose id so I could get the correct hose adapter for the coolant temp sensor. I can pull the hose to find out. I just didn't known if anyone knew offhand.
ooops I was thinking fuel hose .....I was working on a fuel line that a deer broke when I ran it over on my jeep the night i responded so fuel lines were on my mind lol stupid deer.......I guess you probably know its not 1/4 haha.....its has always been a generalized that its 3/4 hose, if I remember any smaller just wont fit although the 3/4 seems too big and bulges a little as you clamp it down.......