Ill check on the hoses after work. What does this vacuum controlled Flo valve loom like? Ill check that also after work. I did my injectors in may. Last winter... my truck would blow hot air at idle. So I'm assuming its something I did. The only thing I mess with is I unplugged the AC compressor. And I noticed that little grey tube wasn't hooked up, so I hooked it up to the little black box above the valve cover.
I think all trucks after 2004 have the vacuum controlled valve. I don't have a picture or diagram of it. If your truck has it, the grey hose goes there. It will be pretty obvious, though. It'll be a valve on the heater hose with a nipple for a vacuum line.
I don't think the valve is your problem. The symptoms don't fit. But it's worth checking. Vacuum should close the valve when the heater control is in OFF and MAX A/C. In all other positions, there should be no vacuum on the grey hose and the valve's spring should open it.
Working on my wife's 2003 Excursion with a 6.0L Power Stroke Diesel
No heat, replaced the heater core,water pump, thermostat we have heat driving down the road but not at idle,Checked the blend door and it opens and closes ,the door is not cracked and the motor appears to be operating normally
The heater core is hot above an idle is so hot you can't touch it, but at a idle its cold. any ideas out there ,Thanks
My typical response would be that the waterpump is not providing enough flow at idle which may be an impeller problem or a housing problem. I just have a problem believing that there are that many pump/housing problems. How's the ECT/EOT delta?