Heater not working can we fix it?

Tiny
MATHEW LINDSAY
  • MEMBER
  • 2001 FORD TAURUS
  • 1.3L
  • V6
  • 2WD
  • 116,000 MILES
My temperature gauge stays on cold all the time and the heat does not get warm.
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Wednesday, February 13th, 2019 AT 12:21 PM

37 Replies

Tiny
HARRY P
  • MECHANIC
  • 2,293 POSTS
Hello and thanks for using 2CarPros.

There are potentially two things that can cause this to happen. The first is that the thermostat, which regulates coolant flow and keeps it from flowing until the engine has warmed up, is stuck in the open position. This would mean that the coolant is constantly flowing at full speed, and keeping the engine from ever getting warmed up. Since your heat is directly derived from the temperature of the coolant, the heat will not get warm either.

The way that your heat works is that coolant flows through a miniature radiator (called a heater core) and the blower blows air through the core, thus warming the air up before it comes out through the vents.

The other possibility, less likely, is that your car is really low on coolant and is just getting enough to keep the engine cool enough. The coolant isn't really reaching the coolant temperature sensor though, so it produces a "cold" signal. Not enough coolant in the system would also affect your heat. Again, this is unlikely because your engine should be overheating, unless you're only running it for a few minutes.

Check your coolant level. It only takes a few seconds. Then, if it's full or even just not horribly low, replace the thermostat. Simply open the hood and take the radiator cap off when the engine is cold (and hasn't run for a couple of hours). If you can see the coolant level in there, then you should be good. If not, add some until it is full, and recheck it after driving a while.

I'm including instructions on replacing the thermostat in the images below and in a general guide.

How a thermostat works: https://www.2carpros.com/articles/how-an-engine-thermostat-works

How to replace a thermostat: https://www.2carpros.com/articles/replace-thermostat

Let me know what you find and we'll go from there.

- Harry
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Wednesday, February 13th, 2019 AT 2:37 PM
Tiny
DESHAZERT
  • MEMBER
  • 1 POST
  • 2001 FORD TAURUS
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 130,000 MILES
The heater throws look warm air at an idle. At higher speeds it gets a little warmer. If I put a thermometer in the radiator, the temp reads 140-150 and obviously the thermostat doesn't open. What would keep the water from heating up. I have never had an UNDER heating problem
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
IBDARTS
  • MEMBER
  • 3 POSTS
Just another thought for ya from my past troubles. When a thermostat gos's bad they are made to get stuck open. That could explain the low heat and warm water temp. Just had a friend with the same problem on a 2000 ford ranger. He replaced the thermostat and had very hot air again. Just a thought for ya, I hope it helps.
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
KELLEOD
  • MEMBER
  • 6 POSTS
  • 2001 FORD TAURUS
  • 3.5L
  • 6 CYL
  • FWD
  • 224,000 MILES
Heater blowing cold air. Through the process of elimination I think I've narrowed it down to a blend door. How many are there and where is the one that controls the temperature? The other doors are working but I can't find the one that controls the temperature. The heater core was eliminated as the source because both hoses are hot, the thermostat was eliminated because the engine isn't overheating and it's running at 188 to 193 degrees. I thought the thermostat might be stuck partially open or partially closed however you want to look at it, but It gets up to temperature like normal as far as I can tell. Any help would be appreciated.
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,606 POSTS
Temperature is about right for your car, so it's not overheating. The blend door is on heater unit it's on the passenger side and you'll have to remove a trim panel to access. Try pulling the hvac fuse in car first for 60 seconds it may reset. Then see if it gets power.
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
SLYDAWG1213
  • MEMBER
  • 3 POSTS
  • 2001 FORD TAURUS
Ok. My car blows hot air for just a minute or so then goes cold on me. If I turn the heater off for a minute then back on. I have hot air again but only for a mintue or so. I have changed the thermostat and with my luck I have cracked the housing. LOL. So I have a new thermostat and housing. I have went in and taken the heater hoses connected them to a water hose and clamped the bypass hose off next to the fire wall and got good clean water flowing through. I did that in reverse as well by changing sides. I have turned the car on and just turned the heater dial from cold to hot on and off to see if the blend door is working. I do hear it running. WHAT IS MY PROBLEM. How do I double check the blend door to see if it is just stuck or stripped or whatever before I spend 8 hours of my day changing a heater core that may not need replaced? Please help me before my wife takes my car and makes me drive hers. Its funny but its that or I fix it. You know the wife will win the battle in the end. So someone please help me. If possible please give detail intsructions or pics. I am not totally a beginner but need help and can follow directions very well if detailed.

Thank you for your time and help.
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
SERVICE WRITER
  • MECHANIC
  • 9,123 POSTS
I want you to bring the engine to operating temperature. Feel both the inlet and outlet hose for the heater core. They both should be hot. Then hold the rpm 1500-2000. Do you get better heat? Higher rpm means higher flow rate and may heat the portion of the core that is not plugged.

There are two common problems with these cars.

First the heater cores are apt to plug up. Having clean water come out when backflushing is a surprise, but flow may still not be what it should be. That is a larger volume of coolant is not going through as it should.


https://www.2carpros.com/forum/automotive_pictures/30961_P2220004_1.jpg

This was a shot of a plugged core after it dried.


https://www.2carpros.com/forum/automotive_pictures/30961_P4250002_1.jpg


Sludge build up in a radiator.

One option to try is to warm up engine then disconnect heater hoses,turned them up and filled core with radiator flush (or muriatic acid-about a 10% solution), left sit a couple hours and then flush again, pull bypass hose and blocked off with a couple rubber caps or however you choose. If both hoses were hot as mentioned in the beginning, then I would expect the heater core should be in an acceptable condition to provide heat.

The second common problem is worn impellers on the waterpump. They erode enough that the coolant circulate not quite well enough to provide heat.
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
SLYDAWG1213
  • MEMBER
  • 3 POSTS
I took the vehicle in to get a power flush. The radiator cap was no good. There was no pressure on the system. I was also told that I had an air pocket in the heater core. So after replacing the radiator cap and flushing the air pocket out (lol) the system works fine.
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
SERVICE WRITER
  • MECHANIC
  • 9,123 POSTS
"See Honey.I told you I had it under control! LMAO!
Congrats!
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
CARJERK
  • MEMBER
  • 1 POST
  • 2000 FORD TAURUS
Why is my heater not working? Control valve?
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
JGONZO2398
  • MEMBER
  • 348 POSTS
I’m having the exact same problem with 02 Ford Taurus! Flushed the coolant system AND the heater core, got a bunch of sludge out until the water started coming out clear. If I leave the knob on hot for a bit then turn on the AC, it comes out hot for a minute then cold. You said radiator cap? I know I might sound stupid but what and where is that? Because I know there’s only a coolant reservoir, and how would you go about fixing an “air pocket” in the core? Because I’m not so sure what that is as well haha
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,544 POSTS
Hello,

There is no heater control valve for the heater hoses that is a temperature blend door actuator that goes out. Here is a guide to give you an idea of what you are in for when doing the job.

https://www.2carpros.com/articles/replace-blend-door-motor

Here is a guide that can help as well.

https://www.2carpros.com/articles/car-heater-not-working

Check out the diagrams (Below)

Please let us know what you find. We are interested to see what it is.

Cheers, Ken
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
CHEVRDNCKP
  • MEMBER
  • 1 POST
  • 2000 FORD TAURUS
Car has no heat heater core was partially clogged and flushed and blend door if at bottom of dash above heater core is working can see actuator move door and have operated door manually with actuator off problem is a/c comes on on every selection except for foot vent and blows ice cold a/c into car regardless of where temp is set at has knobs no climate control
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
BMRFIXIT
  • MECHANIC
  • 19,053 POSTS
This is your problem


https://www.2carpros.com/forum/automotive_pictures/99387_Graphic1_595.jpg



sorry i had no idea it a manual system and not the auto

if you see that the actuator is moving when heat selected and return when cold selected remove blend door actuator and check make sure that the door is moving

this is how to do it
Removal & Installation
Disconnect negative battery cable.
Remove right lower console trim panel from instrument panel.
If equipped with center console, remove right, front side panel from console.
Disconnect A/C electronic blend door actuator connector from actuator.
Remove 4 screws retaining A/C electronic blend door actuator to heater/evaporator housing.
Remove A/C electronic blend door actuator.
To install, reverse removal procedure.
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
TORIE36
  • MEMBER
  • 1 POST
  • 2000 FORD TAURUS
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
When I start my car, occasionally the heater and defrost will not work. No noise or air from the vents. It will eventually turn on once I’m driving for about 30-40 minutes. It doesn’t happen all the time.
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,005 POSTS
Hi,

The vehicle has an engine vacuum controlled mode door actuator. That is the actuator that directs airflow. Now the interesting thing is there is one for defrost and a different one for panel and floor airflow. That leads me to believe there is a vacuum leak.

With the engine running, listen closely for any hissing sounds coming from under the dash. That could indicate a leak.

Next, I attached a pic below showing the defroster vacuum motor. Check the hose going to it to see if it is dry rotted, damaged, or loose.

Also, I'm including directions to replace the panel/floor actuator. This is to help you locate it.

_____________________________________

2000 Ford Taurus V6-3.0L VIN U
Panel, Floor Console Door Actuator
Vehicle Heating and Air Conditioning Air Door Actuator / Motor Service and Repair Procedures Air Door Actuator / Motor, HVAC Panel, Floor Console Door Actuator
PANEL, FLOOR CONSOLE DOOR ACTUATOR
REMOVAL
1. Remove the floor console. Refer to Console.

Pic 2

2. Remove the right-side instrument panel insulator.

Pic 3

3. Working the passenger footwell, remove the floor console register duct vacuum control motor.
1. Disconnect the vacuum hose.
2. Remove the screws.

Pic 4

4. Rotate and remove the vacuum control motor from the floor console register duct door.

CAUTION: Do not attempt to bend any part of the floor console register duct door lever.

INSTALLATION
1. To install, reverse the removal procedure.
Let me know what you find or if you have other questions.

_____________________________________

As I mentioned. Since you have two actuators having trouble, it sounds like a leak and not one of the actuators. If you check the two things I suggested, start the engine and move the hoses around to see if you can hear a leak.

___________________________________

Let me know what you find or if you have other questions.

Take care and God Bless,

Joe
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
FRANO2K3
  • MEMBER
  • 3 POSTS
  • 2000 FORD TAURUS
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 114,000 MILES
Hi, The heat in ma car only works temporary, After the car is on for abt 15 minutes it starts to blow hot air as intended, but then about 15 minutes after that it seems to start blowing cool air or "outside temperature air". This problem has only started abt 2 weeks ago. If I turn the air off for about 10 minutes and turn it on again, then it blows hot air once more for abt 10 - 15 minutes then it gets cold again.
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
BLACKOP555
  • MECHANIC
  • 10,371 POSTS
This sounds like you have low engine coolant or the temperature blend door actuator stopped working but to but sure this video and guide can help us fix it.

https://youtu.be/SNRb6pSwYuU

and if the temperature blend door needs replacement here is a guide that can help with diagrams below to show you on your car.

https://www.2carpros.com/articles/replace-blend-door-motor

This guide can help as well

https://www.2carpros.com/articles/car-heater-not-working

Check out the diagrams (Below). Let us know what happens and please upload pictures or videos of the problem.
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
FRANO2K3
  • MEMBER
  • 3 POSTS
I just found out what was wrong. Real silly, lol. No coolant in car. A gallon of coolant solved the problem. Thanks anyway.
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,005 POSTS
Hi,

Thanks for the update. Absolutely, low coolant will cause the problem. Make sure there are no leaks after you drive it for a bit.

Let us know if we can help.

Joe
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Tuesday, June 22nd, 2021 AT 11:30 AM (Merged)

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