2004 Jetta TDI no heat.

So I bought this car form Florida. They had bypassed the heater core. Reconnected lines that where bypassed. Checked heater. No heat. If I had to guess maybe 65-70 degree at full operating temp(190 degrees) checked both heater hoses going to heater core, both are hot but still no heat. Removed in side panels and checked blend door. Still the same temp. Around 70 degrees. Any other suggestions?


Sent from my iPhone using Tapatalk

Foam on temp blend door or cable to it or the little lever thingy.

Blend door isn’t the issue because I took it apart and it’s still the same temperature


Sent from my iPhone using Tapatalk

Wouldn’t surprise me if the heater core is clogged. Im going to flush it tomorrow


Sent from my iPhone using Tapatalk

Tylere543 said:

Wouldn’t surprise me if the heater core is clogged. Im going to flush it tomorrow


Sent from my iPhone using Tapatalk

Click to expand...

That's what I was thinking, also be sure you don't smell sweet inside the car.
The two reasons I expect the heater core to be bypassed are it being clogged, or leaking. Otherwise, it wouldn't stop blowing hot, which doesn't seem to be the case with it here.
Another thing to check is the passage into the core is clear, could be another blockage in the duct

Sent from my Armor_2 using Tapatalk

Flushed heater core today. It’s has good flow and not clogged. No sweet smell in cab. It’s not leaking. I got some thinking ahead of me.


Sent from my iPhone using Tapatalk

Tylere543 said:

Flushed heater core today. It’s has good flow and not clogged. No sweet smell in cab. It’s not leaking. I got some thinking ahead of me.


Sent from my iPhone using Tapatalk

Click to expand...

You mean it's not leaking enough to show in your short observation. I would think it got bypassed for a reason.

Mine barely had a leak that the shop I use didn't believe when I told them. I said take it apart anyway and I'll cover the labor if I'm wrong. Once they got in there they could see it was starting to leak at the edges. On long drives with the heat going I was starting to just smell it.

Well I bought the car a couple months ago from Florida. I heard a lot of people just bypass it since they don’t use it but I’m not sure because I don’t live in a warm state. Replacing the heater core is the last thing on my todo list. I flushed it for about an hour with water and since I have most of the interior pieces out minus the dash I’d smell or see water dripping.. I let it get the temp and checked the heater hoses and it’s not building pressure like it should I can squeeze the hoses. Lower and upper are hot like they should be.


Sent from my iPhone using Tapatalk

Tylere543 said:

Well I bought the car a couple months ago from Florida. I heard a lot of people just bypass it since they don’t use it but I’m not sure because I don’t live in a warm state. Replacing the heater core is the last thing on my todo list. I flushed it for about an hour with water and since I have most of the interior pieces out minus the dash I’d smell or see water dripping.. I let it get the temp and checked the heater hoses and it’s not building pressure like it should I can squeeze the hoses. Lower and upper are hot like they should be.


Sent from my iPhone using Tapatalk

Click to expand...

Born and raised in Florida myself.
No one goes out of their way to bypass it; it goes bad and leaks and THEN they learn that to be an option.
The northern half of the state; basically Cocoa beach, Orlando and Tampa NORTH is humid and can get cold/freeze(even 40's in FL sucks). Anywhere in those cities or north youll want heat at some point.

So, the blend doors, The metal doors with circles cut out; Have you sealed those circles using a thermal tape or similar?
I thought there was mention of the foam disintegrating, as we ALL have experienced or are experiencing

They have no foam left. I’m going to seal them before I put it back together


Sent from my iPhone using Tapatalk

Tylere543 said:

They have no foam left. I’m going to seal them before I put it back together


Sent from my iPhone using Tapatalk

Click to expand...

welp, with the system open, I'd be checking to make sure the knobs are functioning the guts of it. I'd seal the holes on the door, making sure they're sealed well with a quality metal tape. Heater core already checked out as okay. So, I'd button it up and give it real true test. recirculation button illumated(closed), get to full 190 degrees on the dash, continue to drive for acouple more miles/ several more minutes and then see what you got for heat.
If the fans are working, you should be blowing hot air by then.


I say continue to drive after it reaches 190, before testing; I've read(some of documented) that when you hit 190, straight up and down, the cars actual temp can still be as low as 150 but climbing slowly.
With the car in auxiliary you should be able to click the recirculation button on and off and hear of that motor if functioning.

Thanks for the tips. I’ll let you know how it goes


Sent from my iPhone using Tapatalk