Hello all, I want to install a heater shut-off valve so hopefully my A/C will work better. On a 300 six, does anyone know which way the water flows through the two heater hoses? I seem to remember that the one going into the water pump is the return but I'm not sure if I remember correctly. Any help would be most welcome


Scott in Dallas, Texas
1988 F150 300 w/ T-18

 

I honestly can't remember which way it flows, but I didn't want to leave you hanging on this question.
Unless someone else knows for sure, one thing you could quickly do is disconnect the coil (so it doesn't start), pop a hose off of the heater core, put a small container underneath it, and then have someone snap the starter a few times. If coolant comes out of the hose, that's the out line. If coolant comes out of the heater core, it's the return line.

 

Pump is the return line

 

Thanks!

 

Thanks for the reply!