Folks,

Have tried several things but still at a loss as to why I have no heat in car when dial is set to anything below 24°.

All flaps working. All actuators working. Replaced G13 Mit Silikat Coolant Reservoir with a G12 one. The silikat bag was in tact and had not burst. Replaced Heater Matrix for a brand new one. Mechanic did a few coolant flushes. Still no heat below 24°.

Mechanic now saying that he has heard there are 2 Auxiliary Water Pumps and they could be the problem. Has anybody come across this. Thought changing the actuators and reservoir and Matrix/core and several coolant flushes would solve the problem but no joy. So after a lot of time and expense still no problem. Weird that such a good car in every other way should have this very annoying issue. Mine is 2016 2.0tdi Mk3 DSG.

Any suggestions from the Briskoda Brain Pool greatly appreciated at this stage. Ta.

Just going back to basic principles, it seems the heating does work if the thermostat is set high enough. So no malfunction of the heating system, only its control. Control is based on actual temperature vs set temperature and comes on when set temperature is higher than actual temperature. So one explanation would be the the system thinks the actual temperature is just below 24. A faulty cabin temperature or airflow temperature sensor. No idea where it is, but perhaps it’s value can be read on VCDS etc.

Thanks Nicknorman, see where you are coming from. Maybe someone knows where the cabin temperature or air inflow sensor are located. Appreciate your help. Much appreciated.

Mine has similar trait. In the winter I need to set cabin temp to 23-24deg to achieve maybe 20deg in the car. To much agg to find the root cause so I just live with it.

Thanks Gammyleg. Think I've seen something suggesting that cabin temperature sensor is accessed by (1) Removing side fuse box cover on drivers side (rhd) where you can see the very top of sensor coming up. (2) to access sensor you remove knee height cubby hole on drivers side screwdriver and 4 torx screws plus another one. (3) then look up and see sensor. (4) twist/turn it and then pull it to remove it. (5) disconnect it put new temp sensor in. (6) reverse steps back to beginning to complete. Gonna order new sensor online and give it a shot when it comes 🤞🤞

1 hour ago, TomSko said:

Thanks Gammyleg. Think I've seen something suggesting that cabin temperature sensor is accessed by (1) Removing side fuse box cover on drivers side (rhd) where you can see the very top of sensor coming up. (2) to access sensor you remove knee height cubby hole on drivers side screwdriver and 4 torx screws plus another one. (3) then look up and see sensor. (4) twist/turn it and then pull it to remove it. (5) disconnect it put new temp sensor in. (6) reverse steps back to beginning to complete. Gonna order new sensor online and give it a shot when it comes 🤞🤞

Would be good to know if fitting the new sensor works. Doesn't sound too difficult to replace.

I noticed this on mine too…Had to crank the temp up to get any heat out of the blowers. I haven’t had the car very long so will get a better idea as we approach cooler weather, but it would be good to know if replacing that sensor works for you.

Hi NikiB,

No joy I'm afraid.

Replaced both cabin temp sensors but still no joy.

Its a bit of a joke at this stage.

I've replaced the

Motor Actuators

Heater Matrix/Core

Ambient temp sensor

2 cabin temp sensors

Coolant reservoir

Several coolant flushes

Did hvac recalibration per YouTube numerous times

Still no heat below 24 degrees

Above 24+ it's roasting

A/C is also perfect

At this stage I've done everything that has been suggested.

Bit peed off to be honest that it seems to be such a common prob on VAG cars but they just let it be.

Love the Skoda Superb otherwise but might be time to turn Japanese maybe go for a Lexus for better reliability and a properly working heating system.

Sorry I wasn't more help.

Hope you have better luck.

Wondering whether you could identify and trace the pipework in the engine bay related to the heating system to check if it's all getting up to temperature ( thinking air lock or blockage ).

Relatively easy in an older car but probably not-so in a more 'advanced' vehicle with numerous a/c, vacuum and coolant circuits.

@TomSko Thanks for the update, and sorry you didn’t get to the bottom of it. It’s not bothered me too much just yet…but then again I’ve not been through a winter with it either. Will put this on the “to do” list as I’ve got a couple of issues on mine that I need to sort out first, but will update the thread of if I happen to come across a solution.

@Gammyleg perhaps only if something changes mechanically at 24 degrees - if the system works mechanically above 24 degrees, then there has to be a variable.

@TomSko you mentioned the mechanic said there are 2 auxiliary water pumps...but you didn't say whether they had been changed. Maybe they switch? Or the second adds above 24 degrees (no idea on the logic) so the one that deals with low temperature is failing?

Can you have the system running at 23.5 degrees (assumed no heat), and get someone to flick it between 23.5 and 24 and see if you can hear anything change anywhere? Under the bonnet, under the dash?

@travs No haven't changed the 2 auxiliary water pumps. Will try your suggestion re 23.5 to 24+ degrees and come back. Not getting any error/fault codes re pumps so thought they were OK. Somebody said one is for coolant and one for intercooler but that they are only in play at the very start when engine is cold. Thanks for your help.

@travs tried your suggestion of listening for noise when turning temperature dial and yes there is a motorised sound each 0.5 degree turn up and down in dash so something is happening alright but heat only kicking in at 24+

@Gammyleg please see above update

@NikiB please see above update

Are you trying this with a/c off and auto not selected?

There’s quite a few sensors in play here and at this current climate not getting heat before 24oC sounds right but if you were to repeat this in winter I bet you’ll get heat at 19

Hi Danoid, yes a/c off and auto off. Get your point re current temps but did an airport run at 3AM without outside temp of 13° and same result no heat until dial hits 24°. It's weird.