Please help explain this as I am loosing the plot!

The heating in my 2015 Skoda Octavia 2.0L Diesel is very poor, especially on the passenger side. It takes a long time to heat up, and the air flow isn't great especially on the passengers side. My OBD reader confirms this, after driving for 1 hour, passenger side reads 18 degrees and the drivers side read 40 degrees. (see screenshots). I have checked/done the following:

• Recalibrated the climate system

• Inlet and outlet of heater core are both too hot to touch, so unlikely to be blocked

• I have checked all deflector flaps/servos between the heater core and vents and they are functioning.

• I have checked for blockages between the heater core and vents and there is nothing stuck.

• Cabin filter is ok.

My current thoughts:

• Fan needs replacing? But this wouldn't explain the poor heat.

• Partial blockage on one side of heater core? This might explain the difference in heat between sides.

• I can see with an endoscope that there is clear flow to the core from the vents.

I have attached screenshots from sensors showing temp readings. (What is the windscreen temperature sensor and why is it 18000 degrees?! Could be causing issues?)

Please let me know if you have any ideas as I'm sick or driving to work in the cold!

Edited 12 January12 Jan by Sk0daL0ver

It will probably be the air redirection flap motor that has failed. A read of the codes should confirm this for you. Known issue. Not too hard to replace.

Whilst you are looking at the cooling system, make sure you have removed the silica bag from the coolant header tank. If it is split, then it you need to flush out your entire cooling system. Coolant flush (multiple times) and eventually the silica will come out. Refill using G13 (your 2015 car is the exception to the rule for coolant)

As above, it's either the flap motor has failed or the gears have become misaligned, this can be checked by changing the temperature on the climate control while looking at the motor and it's movement. This is best done with an endoscope, but can be done by removing glovebox (if RHD) or looking up through pedals, but it's quite an awkward position.

Both heater core pipes being hot does not necessarily mean there isn't a blockage, as this was the same on my car, and my matrix was blocked.
I have instructions on how to replace heater matrix, coolant tank and flush coolant on this post

Sorry for the delayed reply. Finally got round to having a look at this today. I followed your instructions and did a full flush, and new heater core + new header bottle and now I have toasty warm heating on both sides!!! Thank you so much for taking the time to post.

Even though the old core was still getting hot, it obviously wasn't getting sufficient flow to heat the air. Just to add to your instructions, I found getting someone to hold the car at approx 1.7K revs sped up the recirculation quite a bit.

Screenshot attached showing temperatures compared to before!