I asked this question in the Ranger forum, but I got no response. Can someone tell me what the hose sizes are for the return and supply heater hoses. It looks like the sizes are different from hose to hose and also from end- to -end on the same hose. One of the hoses I replaced with a custom made aerostar heater hose which was 5/8" at the heater core and 3/4" at the engine. Can someone help me out. Thank you. The engine doesn't have A/C.

 

Maybe you can try talking to the parts department at your local Ford dealership ...you don't have to buy the hose there, but they should at least be able to tell you what size(s) the hoses are, give part #s to match up, etc.