Heater acting up (please help)

[tkoforpresident]

Hey guys, I could really use some help on this one. 2001 Ford explorer 4.0 v6

My heater blows cold for MOST of the time. On the rare occasion it does work it gets cold if I stop driving and gets warmer when I accelerate. The dummy gauge says I'm getting up to operating temps and the radiator hose is hot so the thermostat isn't stuck open and I have the proper level of coolant so that's not it. I took it to a shop yesterday (thinking it was the heater core) and he checked the thermostat first (maybe even replaced it) and flushed out the heater core. After that the heater worked that evening but later in the night it was back to blowing cold as ice.

I've done *some* research and I've read that there could be an air pocket in the system that just needs to be bled. If that's the case, how do you bleed the system on an 01 4.0 explorer? Is there a bleeder screw?

I've also read that it's possibly a vacuum hose issue and there could be a vacuum leak causing the problem. This makes some sense to me and I will now let you guys in on a very key piece of circumstantial evidence.

this issue started almost IMMEDIETELY after I replaced the passenger side head light bulb. In the process I moved around the intake air duct and pushed it back while trying to get the new bulb in. Could I have possibly disturbed an important vacuum hose?

Let me know what you guys think, I really appreciate it.

 

[wood1]

Yeah, I believe there is a vacuum operated shut-off valve on the heater hose for your Ex. Suppose to keep the hot coolant from going to the heater core if you have your A/C on. You probably knocked it off. At least that would make sense.

May not be vacuum... could be cable operated. Ha ha, this is the second time I have said that today... and it could be the blend door in the heater box too.

 

[tkoforpresident]

ok thx, I'll check it out

 

[Turdle]

Low coolant level.
( The volume of coolant missing is replaced with air so air pocket is another term)


Raise the front of the truck high, so the rad cap is higher than the heater core. This will allow the air bubbles to travel up and out the radiator

Then, top off the coolant in radiator and reservoir with 50-50 mix. Run engine with heater turned on, until warm, let cool a bit and re fill coolant. While cooling, squeeze the upper rad hose and listen for bubbles in the reservoir.

repeat until no air bubbles appear.

 

[wood1]

Low coolant level.
( The volume of coolant missing is replaced with air so air pocket is another term)


Raise the front of the truck high, so the rad cap is higher than the heater core. This will allow the air bubbles to travel up and out the radiator

Then, top off the coolant in radiator and reservoir with 50-50 mix. Run engine with heater turned on, until warm, let cool a bit and re fill coolant. While cooling, squeeze the upper rad hose and listen for bubbles in the reservoir.

repeat until no air bubbles appear.

Good advice, I was doing some work on an old E150 years ago and had to remove the return line from the heater core slightly to let air escape while idling. With a cold engine that is. It was the only way I could get the air out if the system. Wear eye pro if you do this.

 

[tkoforpresident]

Thx ill give it a go and report back

 

[tkoforpresident]

How can I tell if the blend door is the problem? I see the write up... looks super easy so I just might do it anyways.

 

[wood1]

It's one of those things that you won't know until you get in there.

Let us know if that was the problem.

 

[tkoforpresident]

Ill give it a shot. Easy fix if it works

 

[tkoforpresident]

OK so i busted a huge hole in the plastic and wormed my hand inside to cop a feel. First I felt the flap to the FAR left but realized that it's only the door that directs the air to different locations. I finally found what I "think" is the blender door but "swinging it" is not at ALL the right term.. This thing would barely budge. That's why at first I didn't think it was it. I don't know if it's stuck OPEN or CLOSE but it's as close to the inside of the cabin it can be and the only other way it moves towards the engine bay is if i push it super hard forward. It's like it's spring loaded or something, I don't know how to explain it. It didn't move AT ALL when changing from AC to heat. Hell, I still don't know if that is the blender door. That thing doesn't barely move an inch let alone "swing" open or close.


WTF? 0.o

 

[tkoforpresident]

Nevermind... figured it out. My blend door is NOT the issue. I still need to bleed the coolant so...