My 2002 Expedition has no heat. The hoses to the heater core are hot and the blend door is working. I cut into the dash behind the glove box with a Dremel and I can see the door moving. Any other suggestions about what my problem could be?
Originally Posted By: outoforder
Both hoses feel hot, antifreeze is full, and truck gets up to temp. What/where is the heater control valve?
I can't find pictures off hand
Open the hood, follow some moderately substantial looking coolant hoses, and you'll be looking for either of these (I suggest you look on the firewall on the passenger side)
Update: Just fired up the truck to make sure all my data I was reporting is accurate. After coming up to temp, the truck will briefly blow hot hair but it quickly fades. While standing in front of the truck, the left hose (passenger side) going into heater core is warm and the hose on the right (drive side) is HOT.
Um, so which hose is which? Instead of disconnecting the hose at the core, what is wrong with cutting the hoses to perform a back flush and then using a plastic barbed connector to reattach the hoses?
With the heater running, the hotter hose is the heater core supply, and the cooler one is the return.
Using a barb connector as a repair will work, but will lower the overall flow. If the barb inner diameter size is about the same as the valve michaelluscher linked, then it doesn't matter.
Flushed the heater core and still no heat. I'm running out of ideas. I also noticed that with heat on, the AC clutch is engaging and disengaging every few seconds. No clue if that could be related.
The AC clutch will cycle if it's a mode that calls for that. Defrost mode has called for AC cycling in Ford and GMs for about as long as I can remember there being AC.
Originally Posted By: outoforder
While standing in front of the truck, the left hose (passenger side) going into heater core is warm and the hose on the right (drive side) is HOT.
Symptoms of a typical clogged heater core or a bad heater control valve which yours has (AKA Ranco valve).
Check the valve with a vacuum pump. Did you back flush the core? Flushing doesn't fix a lot them if it is really clogged.
Yes, I back flushed the core. There was a slight improvement in the heat. I am going to pour a TSP solution into the core and let it sit for a day or two and then back flush again and see what happens.
I usually try to go back and forth in direction when flushing, at least a few times each. Gently though with the pressure and when handling the connections with an older heater core... don't want to blow it.
The TSP solution got some crud out of the system, but I still went ahead with CLR in the heater core. Actually, it was ZEP brand. CLR has gone environmentally friendly. I let the ZEP sit in the heater core for 20 minutes then flushed both directions. I have heat again!