If mine representative, nipple closest to driver was/is return. Bill Robertson #5939 >--- In dmcnews@xxxxxxxxxxxxxxx, "kenndeal" <kenndeal@xxxx> wrote: > Anyone know which side of the heater core is feed and return? I > just did all the water hoses but I forgot to label the pipes that > supply the heater. I know it will work either way but I still > remember my high school auto shop teacher saying they should > not be reversed as lodged debris could back flush into the > system.