No interior heat from Climatronic system

All of Us

Ian's Dad
Joined
Nov 14, 2005
Location
Brookfield, IL
TDI
2015 NMS Passat SE TDI "Gin" 2006 A5 New Jetta TDI "Graycie" and 2003 A4 Jetta GLS TDI "Liath"
Volks:

After doing extensive searching on this topic (Redshed's thread seemed helpful) I need to ask some questions to try and diagnose my problem. Graycie has been having problems sending any heat into the passenger cabin whether through the end, center, floor, or defroster vents. I am leaning towards the issue being caused by a clogged heater core, but I really don't want that to be the cause. I have used my VCDS to run the output tests for the HVAC system and it looks to me like the assorted heating/cooling system doors and flaps are all moving through their entire range of motion as intended and that the 4 different temperature sensors built into the system are giving the correct readings to the system as well. My IR temperature gun is showing that the inlet and outlet (don't know which is which) pipes for the heater core are warm. However one of them is cooler that the other. I have always used the recommended G12 coolant which I purchased form our trusty List Vendors. Am I missing something, or is a heater core replacement in my future? Any helpful help would be appreciated.

Dan
 
Last edited:

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis (where it's safe)
TDI
There are just too many to list....
No DTCs for the crappy Chinese door motors? Then yes the heater core may clogged. Not a bad job. Far easier than those stupid motors. The dash doesn't come out. Little access door down by the pedals.
 

All of Us

Ian's Dad
Joined
Nov 14, 2005
Location
Brookfield, IL
TDI
2015 NMS Passat SE TDI "Gin" 2006 A5 New Jetta TDI "Graycie" and 2003 A4 Jetta GLS TDI "Liath"
Not good news, but thanks or your input!

Oilhammer:

It seems like the heater core (HC) is the likely culprit. Is there always coolant flowing through the HC, and the cabin temperature is controlled by how far the flaps/doors are opened or closed? there were no codes last time, but I will hook up the Vag-Com again to be sure there are no codes now. I see that IDParts wants about $110 for a new HC, are there any other parts that you recommend replacing while I'm in there? If the HC is clogged it should be cool/cold, correct? Is there a way that I can shoot some temperature readings on the HC with my IR heat reader gun to confirm that it is clogged? Any advice or recommendations are welcomed. Also, thanks for your reply, and BTW, I believe we have met at Old Navy's GTG back when he still lived in Poplar Bluff.

Dan
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis (where it's safe)
TDI
There are just too many to list....
The core is likely still "flowing" to some degree, just not through all the little passages required for heat exchange. If you like, you can remove the side cover down by the pedals to expose the two tubes going to and from the core, then drive the car and get it up to temp, then check the tubes to see if they are both hot, and the same temp.

The motors (there are either three or if dual zone, four of them) moves the temp blend door to route the air over the heater core. So hot coolant is always moving through the core, regardless of temp position. Only the routing of air changes. Normally the HVAC system sets a DTC for the motors when they fail. It is, unfortunately, quite common on the NMS, and seems to be much more common on 2015+ cars.





I have done a lot of these.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis (where it's safe)
TDI
There are just too many to list....
I think the OP is talking about an 06 Jetta. Is the advice the same?

You are correct, I did not catch that, sorry. Disregard my above posts as to the HVAC motors, as they do not use the same ones, and I have never seen the temp door motor fail on the A5 (just the recirc motor that breaks). The heater core access is similar, though.

Sorry for any confusion. But hey, you learned something about your Passat anyway! :)
 

All of Us

Ian's Dad
Joined
Nov 14, 2005
Location
Brookfield, IL
TDI
2015 NMS Passat SE TDI "Gin" 2006 A5 New Jetta TDI "Graycie" and 2003 A4 Jetta GLS TDI "Liath"
TDIatLast:

You are correct, the car I am referring to on this issue is my '06 Jetta.

Oilhammer:

Don't worry about the confusion. I do have an NMS Passat and any pointers about that one are welcome too.

I assume that replacing the clamps and seals on the connections at the HC are an "Every time/always replace" situation.

Dan
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis (where it's safe)
TDI
There are just too many to list....
Honestly, the snap connects on the heater core need not be messed with unless there is reason to do so. There is an o-ring inside, you can peer in there and make sure they still look smooth and round, and if they do, you can reuse them.

On the BRM cars, the heater HOSES are usually first to go, as the oil from the breather can often find its way out and leak down on them and swelling the ends, especially the one at the EGR cooler.
 
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