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Heater not working, can't seem to find the reason why - Not the heater core or HVAC Flap

TDISean

New member
Location
Hertfordshire, UK
Car(s)
2013 Golf 2.0 TDI
For reference I have 2013 MK7 Golf 2.0 TDI Blue Motion.

Hi All

About a month ago I noticed the heating wasn't working in my car.
I have now found that if I turn the heater controls to max heat & the fan on 2, I will get a little bit of heat from the drivers side vent next to the window & the center drivers side will be luke warm at best. Both the passenger center vent & passenger vent next to the window are cold.

I've been researching the last couple of week but have yet to find the cause of the issue.

The two main issues I have come across are a clogged heater core due to the silica bag splitting & the HVAC flap motor failing but neither of these appear to be the issue.

Heater core
I have removed the trim in the passenger footwell & took the car for a 10 minute drive.
When returning home, I checked both the inlet & outlet pipe for the heater core, both feel hot to the touch. I also checked with a infrared thermometer & both pipes reading around 30C.
I think it should be getting hotter than 30C but as it was only a short drive, I presume this would be hotter on a longer driver but I think the notable thing is that both pipes were around the same temperature.

HVAC flap motor
Next I checked out the flap motor, which I can see moving from passenger footwell when changing the temperature from cold to hot & back again.
There is also a noticeable sound change in the airflow when doing this which I've read is another way to know the flap is okay.
It doesn't sound like there is anything broken i.e. clicking/scraping etc.

Other things to note
  • I've seen information about thermistors failing but my model does not use these, I think these are only used in new climate control units?
  • The engine temperature climbs normally to 90C & stays there quite happily.
  • Coolant has been checked regularly & it hasn't dropped.
  • I haven't done a coolant change yet as I'd like to fix the issue at the same time I do the change.
  • I did wonder if the issue would be with the heater control valve, but I don't think the heater core inlet pipe would be getting hot if that was the issue?
Any help would be greatly appreciated as the weather is getting colder 🥶
Happy to post photos if needed

Many Thanks
Sean
 

golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
Mk7 Golf GT Estate
I think there is a reset function that by pressing & holding certain buttons it resets the flaps

Only for Climatronic




I'd also check the control module for any fault codes...
 

TDISean

New member
Location
Hertfordshire, UK
Car(s)
2013 Golf 2.0 TDI
Thanks for your reply

Unfortunately I don't have that control unit. I have the one in the photo below. (Taken from Google)

I have just checked for any fault codes with my OBDII reading but nothing to show

1667854561780.png
 

golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
Mk7 Golf GT Estate
Sorry no further ideas!!!..... 🤷‍♂️
 

YamR1rider

Go Kart Champion
Location
Tampa, FL
Car(s)
2017 GTI Sport DSG
I should think you got this sorted out by now, but did you get round to checking out the so called N82 coolant shut off valve? I had a similar problem on my daughters 1.8 Golf TSi, replaced the heater core but it wasn't it - but the valve was. Someone else had written a how to on it, which is here: https://www.vwvortex.com/threads/di...2-heat-taking-a-long-time-to-come-on.9493028/. It may be slightly different for your diesel but principle is the same I'm sure.

For additional info as you mentioned it, it is worth noting that one of the pipes to my heater matrix was also hot even with the defunct valve - it took replacing the valve for the other pipe to become hot. Heat went from nothing/next to nothing to nuclear powered!
 

joeT

New member
Location
Pennsylvania, USA
Car(s)
2015 Golf TDI SEL
Kinda off above subject bit climate control related.
2015 Golf TDI SEL so the Climatic (AUTO) heat/AC system installed.
When digital controls in AUTO set for temperature lower than interior ambient there is plenty of cold air from the center dash outlet. When the selected temperature is higher than the interior temp there is no hot air flow from the top of dash center outlet. There is however adequate heated air flow from the outlets near the far ends of the dash that helps kee the front door windows fog free.
I suspect that the conditioned air that would flow out of the dash center outlet when heat called for is instead distributed down into the foot wells from under the dash. (I have confirmed that there is heated air directed into the front footwells during heat mode)
Can anybody confirm my heated air flow pattern theory? Thanks in advance
 

YamR1rider

Go Kart Champion
Location
Tampa, FL
Car(s)
2017 GTI Sport DSG
Couple of possibilities I can think of - could be either that a flap motor controlling the door (or one of the doors if climatic) to the heater core is not working properly (or some other circulation flap somewhere else maybe). Alternately, before I fixed the N82 valve per my post 5 above, I noticed odd behaviour of some lukewarm heat blowing out the drivers side but not much out the passenger side (on a regular AC car). Switching the valve out fixed all (along with a replacement heater core, my old one was partially clogged). Not entirely sure on the TDI as to whether they have that valve in the same spot as on the gas powered golfs although I would guess there is something similar somewhere.
 
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