bighammer15

Hi guys, I know this has been discussed multiple times on this forum but I have failed to find any good information so I figure to start new. So I have a 2001 F150 4.2 V6, I got it this past spring and it's been a great truck. With the cooler weather setting in I have been needing a little heat to keep my windshield de-fogged, only problem is, I have no heat. I've checked the blend door and it is working fine, no cracks, not loose or anything. I've flushed the heater core in both directions at least 5 times each. I did notice that one of the heater hoses under the hood has been spliced with a hose connector so I checked online to see if this truck had a heater control valve but information is sketchy at best, some say yes, some say no. One thing I noticed that could be a lot of my problem is that the A/C condenser behind the dash is always ice cold, is it supposed to be so? Also is there supposed to be another blend door (or something similar) that separates the condenser from the heating system when the A/C is not running?
Any help would be greatly appreciated.

BlueO2

Thermostat might be stuck open

MCpllabelle

Im leaning towards that as well. Everything you mentioned is normal except you didn't say you checked or replaced the thermostat.

jstockert

How did you verify the blend door is operationable?

nameskreen

I had the same problem for a couple of years. I replaced the thermostat, radiator(started leaking) rad cap, cut the heater box open thinking it was blend door. After flushing heater core several times the heat finally got a little warmer. I flushed it again about a year ago and it started leaking. I replaced it with a Ford core and had great heat.... until this year. I don't know why, but I had to flush it again today. I didn't see any sediment come out, but I have good heat once again. By the way your heater hose may have been spliced because someone may have flushed the heater core before. That's what I did. It was a lot easier than disconnecting the hose from behind the intake.

bighammer15

I cut the heater box open using a dremmel

sam29078

My pickup it doing the same thing. I have flushed core our put in new thermastat water pump. Motor temp is 190 and the hose at heater core are much cool both of them.

jstockert

Are both of your heater hoses getting hot?

bighammer15

Thanks for all the replies and help guys, I really appreciate it.

I don't have a thermometer to check but they both feel hot, in comparison with the radiator hoses they feel about the same, the return line could be a bit cooler but it's a little hard to be exact. After I cut the hole in the heater box the heater core felt really warm, so maybe I am getting too much outside air? Like maybe from where I was running the A/C it's drawing from the outside, I'm not sure.

I have changed the thermostat.

Engine temps are in the 190 range and never overheats.

Also, as of this morning, I flushed the entire coolant system till clear water was coming from every hose, added new antifreeze (2 gallons of full strength and topped the rest off with water. I'll drive it to work this evening and top it off again if needed with 50/50.), new thermostat (again). Also, so you guys know this truck does have a 4 core radiator not the stock 2 core.

The only thing I haven't checked is the water pump.

Side note: this is my 4th F-150 (3rd 4.2L engine) in the 1997-2003 range and this is the 1st time I've ever had this issue.

jstockert

Well in my opinion if your blend door is operating properly and the heater core is not plugged, usually both heater hoses being hot verify it is not, you should have heat in the cab of your truck. I'm sure someone will correct me if I'm wrong. Is your blower motor working?