Join Date: Aug 2010
Location: Sassamansville, Pa
Thanked 195 Times in 157 Posts
Mentioned: 1 Post(s)
Quoted: 0 Post(s)
Feedback Score: 3 reviews
The inline valve is not a back flow control, but a valve that closes off coolant circulation to the heater core to get the cab cooler when using the A/C.
There should be a gray vacuum hose that connects to it.
You could also get the truck up to temp and feel the heater hoses, the hose with the valve is the inlet hose and the other the outlet. See if they feel the same heat temp. If there is a noticeable diffrence, you may have a bad inline valve that isn't opening, air pocket, or blocker heater core.
If both hoses feel the same in temp, you may have a blend door that is not working properly.
Edit: is the coolant in the degas bottle at the proper level?
2004 F350 CC DRW King Ranch
X-3 tunes by DJ'S,QT,GH,ID. Gryphon FICM tunes, ARP studs,Stage 1turbo,ATS coolant recirc lines,Swamp's 48v ficm,coolant filter,AD2,Snow Perf stage II,EGR delete,4" turbo back straight pipe,S&Bintake,Quad "A" pillar autometer gauges,Suncoast Tri Disk Conv.,Billet input shaft,Suncoast superduty rebuild kit,Trans-go shift kit,Mag-Hytec trans pan,CFM+ elbow,ccv mod,15K reese 5er,17" LCD TV/DVD,Cobra 29 Nitewatch CB