heat from passenger vents only

[centerback]

 

Hi,

 

I have a 2014 Octavia mk3.

Recently noticed that hot air is only blowing from passenger side of the car, and getting cold air on the drivers side.

 

anyone have experience of this, or know how to solve it?

 

Car engine temperature is operating at normal temperature... no engine lights on

 

I've tired a few things, but no success so far.

 

I've tried a climate control reset trick a few times (holding down the A/C button &  center vent button)

I even swapped the Left & Right vent temperature sensors around.... but still the same result.

I've reached through the dash, and managed to touch the heater core pipes, and they were very hot

I even hooked up a basic fault code reader, but it said no error codes found.

 

I got down in the footwells and a quick visual inspection of the left & right temperature flap control motors, and they seem to be operating normally... as far as i can tell anyway.

I've attached a pic of the two flap controls, in case anyone spots an obvious issue with them

 

Any other things i should try/check? 

 

any advice much appreciated. cheers.

[Waby88]

I'll also be interested to hear anybody's views on this. I have exactly the same fault, taking the car in Saturday to be looked at so I'll report back if I find anything of use.

[cheezemonkhai]

I’m fairly sure there was a thread about this before and it was a coolant pump or blocked matrix etc.

[Guest J_D]

When my heater matrix clogged due to the "Mit Silikat" bag splitting, the drivers side vents were the first to stop producing heat. 

 

There was a thread a few days ago with similar symptoms I think. 

 

Can you post a picture of the coolant inside your expansion tank? Mine looked horrible before being diagnosed by the garage. It had gone in for a flush as part of the waterpump and timing belt. 

Edited 22 October, 2019 by J_D
Question added.

[3rdoctavia]

Ive got similar issues with my 2016 scout so id be interested in the outcome of this thread.

[Waby88]

7 hours ago, J_D said:

When my heater matrix clogged due to the "Mit Silikat" bag splitting, the drivers side vents were the first to stop producing heat. 

 

There was a thread a few days ago with similar symptoms I think. 

 

Can you post a picture of the coolant inside your expansion tank? Mine looked horrible before being diagnosed by the garage. It had gone in for a flush as part of the waterpump and timing belt. 

My coolant tank is certainly picking up some kind of rust or dirt from somewhere, it has an orange/brown look.

[Guest J_D]

Yeah, I wouldn't be surprised if that is the "Silikat" stuff.

 

My car initially went in for Timing Belt & Water Pump. I had asked them to look at the air from the vents as it wasn't warm, just "not cold" as I usually have the aircon set.

 

The garage advised that the heater matrix was blocked and that it was something they are seeing more frequently now. A heater matrix, new coolant pipes, expansion tank and a flush were required to solve the issue. I went ahead with this as approaching winter I'd need some heat in the car due to my early starts and overnight finishes. Works completed and car picked up with some heat now from the vents.

 

Unfortunately, it turns out my car was one of the worst examples they have seen of the "Mit Silikat" bag splitting. So about 2 weeks I was back in due to bits floating in the expansion tank and the heater matrix seemingly blocking again (heat was there, just not very strong).

 

Before I go any further, I'd like to say the garage I used was amazing. Updates on the vehicle status each day or as they got further into their remedial works. Covered on warranty for the works carried out initially and very helpful. 

The car had multiple flushes and the radiator was removed to perform a flush away from the main system, a new expansion tank and a new heater matrix fitted. They then gave the vehicle back to me to drive for a couple of weeks before I went back in for a further coolant flush to ensure that the "Silikat" material was out of the system.

 

Picture 1 - After the initial flush but before revisiting the garage.

Picture 2 - Before going back to the garage for the revisit (see how much worse this is from Picture 1 taken about 6 days apart).

Picture 3 - Between the remedial works and the final flush. If I saw any in here, I tried to remove it as best as possible to stop it going back through the system.

 

 

 

 

[centerback]

 

Ok, had never heard of the "Silikat" issue before... i'll go check what my coolant reservoir looks like
really hope its not that as it sounds expensive fix!

 

From looking at the Octavia manuals, i'm guessing that all hot air come from a single source, the 'heat exchanger'

see attached image, bit labeled '4'...
coolant heats this exchanger up and the air passes through it and gets heated (...shrug?)
so based on that, i'd either have no heat at all if it wasn't working, or a low amount of heat if it was only partly malfunctioning?

 

but in my case i've got decent heat from passenger side. besides, i reached in and touched the coolant pipes of it, and it was very very hot.

 

that said... it sounds very much like what J_D experienced
 

Quote

When my heater matrix clogged due to the "Mit Silikat" bag splitting, the drivers side vents were the first to stop producing heat. 

 

17 hours ago, Waby88 said:

I'll also be interested to hear anybody's views on this. I have exactly the same fault, taking the car in Saturday to be looked at so I'll report back if I find anything of use.

 

Would be great to hear back about this

[centerback]

 

have attached pics of my coolant tank....

looks like some reddy/orange stuff in it, quite similar to J_D's 😭

 

will bring it into mechanics to flush it out 😫

[Jock]

As someone who noted the same symptoms as the OP and finally had to have the heater matrix replaced due to the silicon filter in the header tank having split, prepare yourself for a rather expensive repair bill.

 

As has been outlined in previous threads and as far as I understand it, there is a bag in the header tank on some models (don't ask me which - it seems to be random!) containing silicon crystals.  This bag splits and the crystals get into the cooling system, then seem to congregate in the heater matrix resulting in that getting blocked - drivers side (in the UK) windscreen starts to steam up and doesn't blow as hot as the passengers side.  You can't leave it like that as sooner or later you'll get a blockage in the cooling system and that means engine problems.

 

It cost me around £800 to have the engine flushed and the heater matrix replaced.

[3rdoctavia]

Hi jock, did the garage know what the issue was straight away or was it one of those things where they pretended yours was the first they'd ever seen with the issue?

And what was the original thing you went to the garage with... ie cold air from drivers side or did you tell them you had a feeling the bag had split ?

Thanks

[Jock]

42 minutes ago, 3rdoctavia said:

Hi jock, did the garage know what the issue was straight away or was it one of those things where they pretended yours was the first they'd ever seen with the issue?

And what was the original thing you went to the garage with... ie cold air from drivers side or did you tell them you had a feeling the bag had split ?

Thanks

The car went in for a scheduled service and one of the comments was "contaminated coolant".  I'd mentioned the driver's side heater was inefficient and the windscreen seemed to take a lot longer to delist on the drivers side.

 

I'd had some issues with coolant during the winter and had had to top up with water only at a motorway service station, but with hindsight, I think all that was part of the problem.  They were going to charge me a lot more, but as the car has been regularly serviced at that particular dealer and it's not the first car I bought from them I did manage to get a significant reduction in what was a very significant price! 

 

To cut a long story short, the dealer noticed the problem after I reported the symptoms.

[3rdoctavia]

Thanks jock. I bought my 2016 scout as an approved used in may so im hoping it will all be under the 12 month warranty i got.

My coolant looks brown , ive got  no hot air from drivers side, only slightly warmer air feom the passenger side, and a coolant tank with the dreaded words "mit silikat" printed on its side .... i wonder what could be wrong 🤔

 cheers

[Jock]

17 minutes ago, 3rdoctavia said:

Thanks jock. I bought my 2016 scout as an approved used in may so im hoping it will all be under the 12 month warranty i got.

My coolant looks brown , ive got  no hot air from drivers side, only slightly warmer air feom the passenger side, and a coolant tank with the dreaded words "mit silikat" printed on its side .... i wonder what could be wrong 🤔

 cheers

Good luck!   Push the warranty for all it's worth!

[Cabman2]

I got this very problem sorted yesterday with my Octavia 1.6 TDI S CR ( 2015 ).  Experienced mechanic spotted that the silicon bag in the expansion tank was adrift and had partially blocked the matrix.  Diagnostics all done.  Had to replace the heater matrix ( backflushing didn't dislodge much),  the auxiliary coolant pump ( gunged up ) and the expansion tank ( filthy ).  80,000 miles.  The surface of the coolant in the tank was brownish, although the rest of it was still largely pink.  £783.  Mechanic's advice on any future Skoda purchase was to bin the silicon bag immediately if fitted and fill up with Volkswagen G13 coolant.  Expensive learning curve and damn you Skoda for fitting it in the first place.

[3rdoctavia]

Mine is booked in for next week 🤔

Should this be covered under the skoda 12 month used car warranty as i only bought it in may at 3 years old and 29k on the clock ?

Thanks

[Oldmansomerset]

Just read this.  What is the purpose of the silicon bag and where should it be located please.  Hope I haven't missed the point.  2017 Octavia 1.5TSI

[Cabman2]

4 minutes ago, Oldmansomerset said:

Just read this.  What is the purpose of the silicon bag and where should it be located please.  Hope I haven't missed the point.  2017 Octavia 1.5TSI

 

It's in the coolant expansion tank and I believe it's to help with corrosion in the engine block.  I don't know if it floats or is fixed,  or even if your particular model has one,  but if if it bursts it makes its way around the system and eventually ends up blocking ( or at least partially blocking ) the heater matrix and you end up with little or no heat coming out of the air vents on the dashboard.  If the bag is burst,   bits of it also reside in the expansion tank as a blackish/brownish crud floating on top of the surface of what should be clear coloured coolant.  My mechanic has done lots of these and he immediately smelt the silicon when he popped open the expansion tank lid.  As a matter of course he replaced the expansion tank with a non-bagged new one,  and also replaced the auxiliary coolant pump which in his experience also gets gunged up.  It goes without saying that the whole system needs a thorough flush to purge the silicon.

 

An expensive repair unfortunately,  but all is fine again in my car,  all vents blowing good hot air within 4 or 5 minutes of running from cold.   I wish I had known about this silicon bag  problem earlier,  I would have binned it long before now and settled for a high grade coolant on its own.  I don't know if removing the bag would affect your warranty,  my car is well out of warranty and is running with Volkswagen G13 coolant as recommended by the Skoda/Volkswagen mechanic.

 

 

[Nickj633]

My own response to this problem will be to remove the bag, fill up the displaced amount with G13, then remember to have the fluid changed every 2 years. Mine is well out of warranty, and with the fluid still a clear pink colour, will hopefully avoid the issue before it starts.

i can understand VAG’s get around with trying to prevent issues with the heating matrix by adding a slow dissolving silicate, however their engineering approach seems to be a bit hit and miss.

[Oldmansomerset]

Many thanks for the info.  Mine is still nice and pink and I will go and see if I can find this bag and get rid of it if fitted.  I'll let you know idc.

[Nickj633]

Just be careful that the bag doesn’t split if you try and remove it....

[Dave_N87]

Hi all, my Octavia 2.0 2014 is having/similar the issue with the heater/coolant. I've not heard of this bag before. Does anyone have a picture/diagram of the bag? to show what I should be looking for in mine. (If I have one or not).

[Guest J_D]

So, slightly dragging this up, apologies. 

 

@Cabman2, seems you paid a price very similar to me. After my car's 2nd visit to the garage, it seems fine now. 

 

I've still a small amount of silicon floating in the coolant (extremely minimal), but it is a slow dissolving silicon from my research online so overtime I imagine this will clear up. My heater matrix is also still working well - heat from all vents. Good level of heat also. My coolant level isn't dropping either as it previously had so I'm fairly happy that this is resolved for me now - fortunately as finishing a night shift with a frozen car would not be fun without a working heater!

 

@3rdoctavia, how did your investigations go?

 

@Oldmansomerset, I think the silicon bag is only in diesel vehicles. You'll identify whether yours has it as the expansion tank will have "Mit Silikat" stamped on it. 

[Cabman2]

@J_D  Yep,  everything back to normal now 😁.  Just as well,  I'm out the house at 4am routinely and I need my heat in this chilly weather, lol.

[3rdoctavia]

I got mine sorted under the approved used warranty the other week. Drained the system and flushed it along with changing heater matrix and filler tank. Everything is nice and warm now.

At the end of the warranty im going to bin the silica bag and just siphon and top up the coolant every now and then.

Its a shame that such simple thing can cause an issue which can cost a grand to fix .