As per title, turn heating on and blows hot on passenger side and cold driver’s side.

I have read many post that suggests it could be heater matrix being blocked, however (I could be wrong of course) I don’t think it’s this because that the silica bag has already been removed before it had a chance to burst! And the coolant looks nice and fresh/clean.

so could it be a flap or a sensor? I’ve tried looking for drawings to help me locate where these would be so I can check but not found anything!

any help appreciated.

Thanks

 

 

Do you have a Fabia or Octavia?

Have you tried a simple recalibration?  Dependent on age and model this might be helpful:

 

 

 

Gaz

23 minutes ago, ords said:

Do you have a Fabia or Octavia?

Octavia mk3

16 minutes ago, Gaz said:

Have you tried a simple recalibration?  Dependent on age and model this might be helpful:

 

 

 

Gaz

Yes have given this a go but still the same unfortunately! 

Cold drivers side is classic MQB matrix blockage… it’s coming up to that season again. I have personally never seen the Silicate bag or cartridge burst, it was there to boost the Silicate levels in the G13 coolant which has now been superseded by G12 Evo. We but this from TPS in 20 litre drums of concentrate and then mix 60% Quantum mixing water and 40% G12 Evo. You can buy ready mixed but it is 50/50 and a little on the strong side for our needs in the UK.

10 minutes ago, Crasher said:

Cold drivers side is classic MQB matrix blockage… it’s coming up to that season again. I have personally never seen the Silicate bag or cartridge burst, it was there to boost the Silicate levels in the G13 coolant which has now been superseded by G12 Evo. We but this from TPS in 20 litre drums of concentrate and then mix 60% Quantum mixing water and 40% G12 Evo. You can buy ready mixed but it is 50/50 and a little on the strong side for our needs in the UK.

So you think the matrix could still potentially block even though there’s no silica bag present and coolant looks to be clean? I might have to remove the matrix an flush/ check it if that’s the case.

But would like to try the easy options first if I can find out where to find this flab and sensors?!

 

I think it's more likely do be stuck director flaps; 10 minutes of flapperobics might help.

26 minutes ago, KenONeill said:

I think it's more likely do be stuck director flaps; 10 minutes of flapperobics might help.

Is it possible to access the director flaps? Can’t find any drawings to indicate where they are located. I guess it will be either side behind the stereo within the dash somewhere or could it be behind the centre vents?! 
Thanks

As ken alluded to, just sitting with it on and moving the flap position "manually" a large number of times by pressing the button for feet, windscreen, face over and over whilst also setting lo and hi over and over might be enough to free something. It's worth a try for nothing.

 

I think the diagnostic tools might be able to do some playing around with this too.

Look at this thread. 

 

22 hours ago, dewindoeth said:

So you think the matrix could still potentially block even though there’s no silica bag present and coolant looks to be clean? I might have to remove the matrix an flush/ check it if that’s the case.

But would like to try the easy options first if I can find out where to find this flab and sensors?!

 

 

The Silica bag not being present will contribute to the problem. G13 is Si-OAT (Silicated HOAT) – i.e. Silicates and organic acids. The bag of additive never splits in my experience, it is there to prevent Silicate falling out of suspension and blocking the matrix. Flushing the matrix doesn't work, once it is out, change it. Only use G12 Evo and if mixing, only use distilled water.

 

 

 

 

 

 

 

 

2 hours ago, Crasher said:

 

The Silica bag not being present will contribute to the problem. G13 is Si-OAT (Silicated HOAT) – i.e. Silicates and organic acids. The bag of additive never splits in my experience, it is there to prevent Silicate falling out of suspension and blocking the matrix. Flushing the matrix doesn't work, once it is out, change it. Only use G12 Evo and if mixing, only use distilled water.

 

 

 

 

 

 

 

 

Thank’s I will ensure G12 Evo is used when I flush and replace the Matrix. 

We use an decent aftermarket matrix such as Nissens but you still need to buy the genuine fitting kit or they leak.

Edited 23 September, 20223 yr by Crasher
spelling

On 23/09/2022 at 11:56, Crasher said:

We use an decent aftermarket matrix such as Nissens but you still need to buy the genuine fitting kit or they leak.

Thanks Crasher,

I have seen the Nissens matrix but not the fitting kit! Where did you get this from?

Also, in regards to the coolant, I presume it’s best to get ready mixed G12 Evo? As I’m not sure where I could get enough distilled water of this volume to mix with. ( I believe the coolant capacity in this vehicle is 12l?)

The fitting kit is genuine dealer only 5WA 815 155 and costs £13.48 BUT this is assuming you have the common Valeo system not Denso, interestingly I have yet to see this problem on the MQB platform fitted with the Denso system but it is much less common.

23 minutes ago, Crasher said:

The fitting kit is genuine dealer only 5WA 815 155 and costs £13.48 BUT this is assuming you have the common Valeo system not Denso, interestingly I have yet to see this problem on the MQB platform fitted with the Denso system but it is much less common.

Thank you once again for your input.

I guess I should be able to see what system I have by removing the plastic cover holding the matrix in place?

Not even that hard, just access the cabin filter cover… at least it isn’t a Golf 7, I hate doing those, crap design. Take care with the light switch rack, they are fragile.

Finally had the chance to have a look. And it appears that I have the Denso type Matrix which seems to be less common, but suprisingly cheaper compared to the Valeo type! 
Is the fitting kit 5WA 815 155 the same for Denso type?

Bit of an update. Matrix replaced along with G12evo coolant. Both passenger and driver’s side is now warm and toasty 😊

On 21/09/2022 at 12:39, Gaz said:

Have you tried a simple recalibration?  Dependent on age and model this might be helpful:

 

 

 

Gaz

De what do you do if you don't have that setup and only have manual knobs

On 21/09/2022 at 14:58, KenONeill said:

I think it's more likely do be stuck director flaps; 10 minutes of flapperobics might help.

What if you don't have the climatological control and just the manual how can you do the flaps

Sorry to jump in on this old thread. I sent my 2014 Octavia mk3 in for a coolant/antifreeze change as I've opted to go another year or two before I change the timing belt and the coolant was looking very brown. Garage reported when flushed it was heavily contaminated and the silica bag had burst and has now been removed. Shame I didnt know this had all been done and put back together before I collected it as Id have said about replacing the matrix as Id read about it last winter as I noticed the heating was naff. 

 

Anyway... I think I have a Denso heater matrix need to double check before ordering a new one. Hoping to change it out next week if I can get the parts. Racing the colder weather. Can I ask what brand matrix you ended up buying? Will I get away with taking out the matrix without emptying the system before hand as its obv just been changed? be easier if I could just top up what I lose.... thats unless removing the matrix without emptying the system is going to flood out the entire footwell. Don't fancy that ahah

Hi there

just looking for some help here. I recently purchased a Skoda Octavia elegance. When I put on the heating it blows warm air out the the passengers side but cold air out the drivers even though they are both set at 30 degrees. I’m worried it might be my head gasket, is this a possibility? 

1 minute ago, Gary34 said:

I’m worried it might be my head gasket, is this a possibility? 

Very unlikely, the passenger and driver side heating comes from one common heater matrix.

 

Far more likely is a problem with the temperature flaps in the HVAC system, you really need to get a scan done with a diagnostic tool such as OBDeleven or VCDS to get the details.

1 minute ago, Gary34 said:

Hi there

just looking for some help here. I recently purchased a Skoda Octavia elegance. When I put on the heating it blows warm air out the the passengers side but cold air out the drivers even though they are both set at 30 degrees. I’m worried it might be my head gasket, is this a possibility? 

If it's climate control there is a reset for the electronic vents I think which could be worth trying. I have the older manual controls so I can't help you there I'm afraid.

 

I reckon it will be your heater matrix. I had the same. Silicon bag in the expansion tank had burst and contaminated the coolant. Flushed the coolant system, changed the expansion tank and replaced the heater matrix and it's all good now