2012 Explorer Heat Issue

[nadorp]

Hello Guys, new here!
I'm having a heating issue and was hoping I could find the answer here. How could I loose with all the vast knowlege here.
My Explorer has a heating issue. Once in a while it will blow warn air. Rarely. But 99% of the time it just blows cold. I have dual climate and rear climate control and all including defrost blows cold. I have taken the dash apart and checked the blend doors and actuators and all are good and working. I am really stumped as to what it is. One thought was a control valve in a heater hose under the hood, but I read somewhere they stopped using them before 2012?? Coolant level is fine and there are no leaks anywhere.
I really appreciate any help.
Thanks!

 

[peterk9]

Welcome to the 5th gen Forum.
Possibly a stuck thermostat? Have you been checking the temperature gauge to see if it reads hot? I believe there is also an HVAC control module.

Peter

 

[nadorp]

Welcome to the 5th gen Forum.
Possibly a stuck thermostat? Have you been checking the temperature gauge to see if it reads hot? I believe there is also an HVAC control module.

Peter

Yes the temp guage stays normal. No issue there. Do you know where this HVAC control module is?
Thanks!

 

[ProjectSHO89]

Before doing or looking at anything else, you need to determine whether or not hot coolant is flowing through the heater core when you encounter the loss of heat.

If there is no supply of heat to the system, nothing else (blend doors, control module, etc) really matters.

If there is no hoot coolant flowing through either heater core at the same time, that would suggest that either the system is low on coolant, there are air locks in the system, or the water pump ain't pumping. The "temperature gauge" isn't a particularly accurate indicator of the cooling system's operation. It can show you if you have a problem but really can't be relied on to rule out a problematic condition.

 

[Odrapnew]

Before doing or looking at anything else, you need to determine whether or not hot coolant is flowing through the heater core when you encounter the loss of heat.

If there is no supply of heat to the system, nothing else (blend doors, control module, etc) really matters.

If there is no hoot coolant flowing through either heater core at the same time, that would suggest that either the system is low on coolant, there are air locks in the system, or the water pump ain't pumping. The "temperature gauge" isn't a particularly accurate indicator of the cooling system's operation. It can show you if you have a problem but really can't be relied on to rule out a problematic condition.

That.

 

[nadorp]

Before doing or looking at anything else, you need to determine whether or not hot coolant is flowing through the heater core when you encounter the loss of heat.

If there is no supply of heat to the system, nothing else (blend doors, control module, etc) really matters.

If there is no hoot coolant flowing through either heater core at the same time, that would suggest that either the system is low on coolant, there are air locks in the system, or the water pump ain't pumping. The "temperature gauge" isn't a particularly accurate indicator of the cooling system's operation. It can show you if you have a problem but really can't be relied on to rule out a problematic condition.

Good info!
I can rule out air locks and low fluid. I need to find the heater core so I can determine if it's warm when at temp. With over 100k the water pump could be bad.
Thanks

 

[MAS Tequila]

With over 100k the water pump could be bad.

You had better hope the pump isn’t bad.

Sounds like the blend door or motor.

 

[nadorp]

With over 100k the water pump could be bad.

You had better hope the pump isn’t bad.

Sounds like the blend door or motor.

Like said earlier, blend doors and motors already checked and all good. I need to check the heater core and water pump. Is the water pump hard to change?
Thanks!

 

[peterk9]

Like said earlier, blend doors and motors already checked and all good. I need to check the heater core and water pump. Is the water pump hard to change?
Thanks!

Have a look at this thread; List of Useful Threads - 3.5L Water pump replacement - Gotchya's

Peter

 

[The D]

Like said earlier, blend doors and motors already checked and all good. I need to check the heater core and water pump. Is the water pump hard to change?
Thanks!

The water pump is not especially difficult but it is a lot of work. In addition to the thread Peter linked to, I also wrote up a step-by-step thread that’s stickied at the top of the ‘11-‘19 explorer section. If you’re even a little mechanically inclined and don’t needlessly rush the process it’s not bad

 

[nadorp]

OK, after further investigation, engine warms up to temp fine. No over heating. The upper and lower radiator hoses are warm. The 2 heater core hoses from the engine to firewall are cold. Coolant level good. No visible leaks.
If this were an older vehicle I would say the heater control valve was bad but apparently this year doesn't use one any more. With that said, is there something that replaced the control valve that could have gone bad?

 

[nadorp]

Ok guys. Here we are closing in on 1 year since this problem started. I wanted to update this and share where we are, hoping if we can fix this problem , someone else with a similar problem won't go through what I have been through.
So, last winter I never found the problem and the car sat until May. Because it sat, the battery went bad, the plugs went bad, the alternater went bad. So, after replacing all that including a belt, thermostat and coolant, it seemed to me to blow heat. So, I thought the new thermostat fixed the problem. I went on several long trips since with this car. I am 99.999% sure the water pump is fine. Of course the problem came back. Well, I have ruled out both front and rear heater cores due to no heat front or rear. The problem if not a plugged Hose, is in the engine. So, if it is not the water pump and thermostat, what else could it be?????
Thanks guys!

 

[peterk9]

Have you ever checked to see if there has been a fault code set?
Have you had the HVAC control module checked? Have you ever taken it to a dealer or garage to have it diagnosed?

what does the hvac control module do - Google Search

Peter

 

[nadorp]

No codes.
I went out tonight to vote and the heat worked great. Nice and hot. I came home and parked and it turned cold again???

 

[texsn95]

Do you have a point and shoot temp gun? If not, get one of those first so you can confirm how the hoses are warming up in relation to each other. This sounds like air trapped somewhere back there. Did you confirm if there was a heater control valve inline somewhere? Our Armada has one and it's always screwing up, I hate it. I'd start with jacking the front end up, opening the expansion tank, turning the heater on full blast and start squeezing on the heater lines. Check the expansion tank to see if any bubbles make their way back out of the system. Especially since you had the system opened up and could have entrained some air in there.

 

[peterk9]

No codes.
I went out tonight to vote and the heat worked great. Nice and hot. I came home and parked and it turned cold again???

Going back to an earlier post you said the heater core hoses from the engine to the firewall were cold. Isn't that an issue? If they are cold, you aren't going to get any heat. Might be time to take it to the dealer or another independent garage to have it checked out.

Peter

 

[nadorp]

Do you have a point and shoot temp gun? If not, get one of those first so you can confirm how the hoses are warming up in relation to each other. This sounds like air trapped somewhere back there. Did you confirm if there was a heater control valve inline somewhere? Our Armada has one and it's always screwing up, I hate it. I'd start with jacking the front end up, opening the expansion tank, turning the heater on full blast and start squeezing on the heater lines. Check the expansion tank to see if any bubbles make their way back out of the system. Especially since you had the system opened up and could have entrained some air in there.

They stopped using the control valves in 2010. This problem started with over 100K miles so I doubt it's trapped air. I wonder if there's another "blend door" farther back in the dash? I took apart the passenger side of the dash to check the blend doors but I don't know how many there are.

 

[nadorp]

Going back to an earlier post you said the heater core hoses from the engine to the firewall were cold. Isn't that an issue? If they are cold, you aren't going to get any heat. Might be time to take it to the dealer or another independent garage to have it checked out.

Peter

Yes when the heat isn't working. But when it does, it's fine. That is what is so bizarre. Before I give up and take it to the dealer, I will continue to search for answers. That's what this forum is for. I have worked on cars for 46 years and my son went to college for automotive. Yes we are stumped now, but are hopeful we can figure this out. I have a friend who is a mechanic at a Ford dealership and he is stumped too.

 

[peterk9]

They stopped using the control valves in 2010. This problem started with over 100K miles so I doubt it's trapped air. I wonder if there's another "blend door" farther back in the dash? I took apart the passenger side of the dash to check the blend doors but I don't know how many there are.

Don't know if this helps.

Peter

 

[ProjectSHO89]

I wonder if there's another "blend door" farther back in the dash?....... Yes when the heat isn't working. But when it does, it's fine.

Well, to re-emphasize, if the hot coolant isn't circulating through the heater core, the temperature blend door doesn't matter.