No Heat only cold air blowing

[01expxlt]

I have a 01 Ford Explorer w/ 4.0L V6 engine. The heat was coming and going then it just stopped blowing hot air all together. I checked the radiator and the cap was cold so i changed the thermostat and it didnt help any. The lower radiator hose is cold and the upper is hot but not that hot. The outer heater hose which has the heat control valve on it is hot and the inner hose is cool. the car is not over heating so i dont think it is the water pump but i am not sure. can someone help please

 

[bobflood]

I have a 01 Ford Explorer w/ 4.0L V6 engine. The heat was coming and going then it just stopped blowing hot air all together. I checked the radiator and the cap was cold so i changed the thermostat and it didnt help any. The lower radiator hose is cold and the upper is hot but not that hot. The outer heater hose which has the heat control valve on it is hot and the inner hose is cool. the car is not over heating so i dont think it is the water pump but i am not sure. can someone help please

Is the heater control valve working - that is, does it move when you turn the heat on?? If no, that's your problem.. If yes, then next thing to check is the blend door - a know weak point on these vehicle.

 

[McWiggles]

heater core 100%

 

[drbenz]

If the change to cold was sudden then the valve or blend door are likely but check all of your fuses, it's cheap and easy (personally I hate it when I get stung by something simple).

 

[koda2000]

could be several things. low coolant, stuck thermostat, bad heater control valve, blocked heater core, blend door issues. I'd start with the coolant level and themostat (i see you say you've changed the tstat) then the control valve. what temp tstat did you put in? should be 190-195 degree.

 

[cageglitz]

I'm having the same problem and was told it the door, I've priced it out and so far getting like 500-700 to fix it does any one know of a cheaper way to get fixed ?

 

[masospaghetti]

There's a step-by-step on how to cut the heater box and install a new door, it's not hard. I believe "Magicland" is the user that posted it. I bought a hot knife and it cut through the heater box easily (basically a soldering iron with a utility blade). Old door fell right out after cutting for about 30 minutes.

New door is available at Napa for about $15.

 

[Mustang351cca]

Well, mine was a little different than that... I turned on the heat one day on my way to work and had now heat, just cool air. When I got to the shop I checked the coolant level (fine), hot upper and lower rad hoses, hot heater hose inlet, but cold outlet... So just out of curiosity I pulled the vacuum line going to the Heater Control Valve and it opened, everything was fine till I started my truck later on that night to go home and the same thing all over again, this time I went under the hood and just unplugged the vacuum line all together just till I can figure out what is wrong... BTW it is a new valve that I put in not too long ago..