Heater core replacement?

Tiny
KIDPLASMA
  • MEMBER
  • 2005 VOLKSWAGEN JETTA
  • 2.5L
  • 5 CYL
  • 2WD
  • AUTOMATIC
  • 155,750 MILES
About twice a month I have to add coolant. I don't see any leaks underneath the car or hood. The car hasn't ran hot just going down. I've only had the car for 4 months I need help. Thank you.
Wednesday, February 10th, 2021 AT 2:56 PM

13 Replies

Tiny
SEVAG P
  • MECHANIC
  • 405 POSTS
Hello.

you must pressurize the coolant system first to detect coolant leak, sometimes leak can be too small only can be detected at high pressure.

check our guide below how to check

https://www.2carpros.com/articles/car-is-leaking-coolant

https://www.2carpros.com/articles/coolant-leak-symptoms

Hope these help.

thank you.
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Thursday, February 11th, 2021 AT 11:25 AM
Tiny
KIDPLASMA
  • MEMBER
  • 3 POSTS
Thank you as I've had time to think about it I remember smelling some coolant inside the car. Is it possibly the heater core? There's no leaking inside of car just curious. Thank you in advance.
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Thursday, February 11th, 2021 AT 5:28 PM
Tiny
KIDPLASMA
  • MEMBER
  • 3 POSTS
One more thing; is it possible or recommended if it is the heater core could I or should I use radiator sealant until I can get it repaired?
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Thursday, February 11th, 2021 AT 5:45 PM
Tiny
SEVAG P
  • MECHANIC
  • 405 POSTS
Hello,

yes, it's possible from a leaky heater core, to make sure remove the surrounding carpets pressurize the system you must detect the leak because its present you can smell it.

i prefer to use liquid radiator sealant not the powder type, and use good known brand, it can seal only the small leaks. you can try.

https://www.2carpros.com/articles/replace-heater-core

Check our diagrams below how to replace heater.

let us know if you need more help.

thank you.
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Friday, February 12th, 2021 AT 10:32 AM
Tiny
SHAWNA87
  • MEMBER
  • 4 POSTS
  • 2001 VOLKSWAGEN JETTA
  • 150 MILES
My car stopped producing heat a few months ago. The thermostat was replaced first, still no heat. The heater core was flushed, no heat. I also replaced the temp sensor, blower motor and water pump and finally the heater core. Still no heat! At idle the cabin gets warm, when increasing Rpm's the air becomes cold again. I pulled the dash apart and got to the blend doors. I moved them manually and they are not stuck or broken. Any solutions?
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Friday, February 12th, 2021 AT 12:13 PM (Merged)
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
What do the heater doors look like? Are they shiny with holes in them?

Are both heater core hoses hot to the touch?

Thomas
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Friday, February 12th, 2021 AT 12:13 PM (Merged)
Tiny
SHAWNA87
  • MEMBER
  • 4 POSTS
Both lines are hot to touch. Yes the heater doors look like that.
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Friday, February 12th, 2021 AT 12:13 PM (Merged)
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
The foam is missing from the doors... that is why you are not able to direct the cold air past the heater core to get warm.

The doors need to be re-lined with foam.

Watch my Eurovan heater core video:

http://www.youtube.com/watch?v=FQcL2PMRqgc

At 8:05 you will see the same doors with no foam.

Fix the doors and you will have heat again!

Thomas
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Friday, February 12th, 2021 AT 12:13 PM (Merged)
Tiny
SHAWNA87
  • MEMBER
  • 4 POSTS
Sorry for not getting back to you. The foam is actually not the problem. Any other ideas?
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Friday, February 12th, 2021 AT 12:13 PM (Merged)
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
Then this is something I can't guess over the internet. I would have to have the car in my hands.

Manual or climatronic heater panel?

If climatronic, run basic settings to reset the motors / flaps.

Thomas
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Friday, February 12th, 2021 AT 12:13 PM (Merged)
Tiny
SHAWNA87
  • MEMBER
  • 4 POSTS
I have manual heater controls.
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Friday, February 12th, 2021 AT 12:13 PM (Merged)
Tiny
MWEELS1
  • MEMBER
  • 5 POSTS
  • 2000 VOLKSWAGEN JETTA
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 133,000 MILES
My jettas heater does not work. The car runs about 190 degrees which is what my 03 Jetta runs. Air cond. Works great, it does not over heat and there are no leaks. There is also no antifreeze smell or humidity in car. When I check the 2 hoses that go through fire wall into the heater core, I can feel that one is hot and the other is not which would indicate that there is not any flow. I cant tell if there is heater control valve in the car and is it posible that the heater core is bad even though there are not any symtoms. I also reached under dash and could feel the door open and shut when I turn the hot/cold control dial.
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Friday, February 12th, 2021 AT 12:13 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,136 POSTS
On the 2000, I believe there is a control valve. It will be mounted in one supply line of the heater core. If there isn't one, then remove both hoses to the heater core and see if you can get water (from the hose) to pass through it. IT could be plugged.

Let me know what you find.
Joe
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Friday, February 12th, 2021 AT 12:13 PM (Merged)

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