heat from passenger vents only

[StephenVRS]

I have a 2014 2.0 TSI Vrs 220 and I had the "Mit Silikat" bag in my expansion tank. So it is not only diesel vehicles!

 

I recently got my local independent garage (who I have been using for years) to drain the coolant which was still a slight pinkish colour, and the bag had not apparently split, and to replace the expansion tank with a new one without the bag. And refill with G13 coolant.

Total cost including all parts was 105 pounds.

 

So even if they have to drain and replace the coolant every couple of years that would still take about 20 years to cost approximately 1000 pounds which appears to be the ball park for a new matrix replacement?

 

Means I will not have this issue of a clogged up matrix. More so as I tend to keep my cars for years. I had a Volvo T4 that I had until I wore it out! so for me a ‘no brainer’ decision to get this done.

[Topman121]

On 24/10/2019 at 15:18, centerback said:

 

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 😫

Centre back did you get this sorted my car is doing the exact same thing and coolant looks the same as this also?

On 24/10/2019 at 15:18, centerback said:

 

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 😫

Centre back did you get this sorted my car is doing the exact same thing and coolant looks the same as this also?

[allan1888]

1 hour ago, Topman121 said:

Centre back did you get this sorted my car is doing the exact same thing and coolant looks the same as this also?

Centre back did you get this sorted my car is doing the exact same thing and coolant looks the same as this also?

Chances are your coolant expansion tank has "mit Silikat" on it and has the silicate bag in the tank. Possibly it has ruptured blocking your heater matrix 

[Topman121]

8 hours ago, allan1888 said:

Chances are your coolant expansion tank has "mit Silikat" on it and has the silicate bag in the tank. Possibly it has ruptured blocking your heater matrix 

Thanks Allan my tank has got that on it! Coolant level is also going down topped up twice in 300 miles it’s back below minimum again all inside 2 weeks, I’ve ordered new t belt kit and water pump maybe it’s leaking? No leaks from underneath as it was serviced last week and all is clean. Also new upgraded coolant tank ordered without “ mit silikat “ on it all genuine from Skoda. Would it be worth flushing heater matrix with I’ve the system drained?

[allan1888]

No harm in flushing the system through, the heater matrix may need replacing if it's blocked and cant be flushed. I'm guessing that you are out of warranty ?

[Topman121]

21 minutes ago, allan1888 said:

No harm in flushing the system through, the heater matrix may need replacing if it's blocked and cant be flushed. I'm guessing that you are out of warranty ?

Yes Allan car is out of warranty from June last year, I’ve removed the passenger side lower panel to access the heater matrix and both pipes entering and exiting the matrix are very hot to touch making me believe the matrix isn’t blocked? It’s had an EGR cooler fitted in December 2018 by Skoda before I bought it, car has full Skoda history up to November 2019

[allan1888]

Sometimes Skoda will offer a goodwill contribution to repairs with a full dealer history, but not sure how it works as I had a hard enough time getting work done while under warranty even worse when warranty only had 6 months left 😂😂

[Topman121]

26 minutes ago, allan1888 said:

Sometimes Skoda will offer a goodwill contribution to repairs with a full dealer history, but not sure how it works as I had a hard enough time getting work done while under warranty even worse when warranty only had 6 months left 😂😂

I would well believe it! 😂 I’ll update you on the coolant loss side of it when I do the t belt and water pump on Monday see if the pump is actually leaking or not. Cheers again Allan!

[allan1888]

49 minutes ago, Topman121 said:

I would well believe it! 😂 I’ll update you on the coolant loss side of it when I do the t belt and water pump on Monday see if the pump is actually leaking or not. Cheers again Allan!

Hopefully it's an easy fix, I changed my coolant expansion tank purely to save any issues.

[Topman121]

8 minutes ago, allan1888 said:

Hopefully it's an easy fix, I changed my coolant expansion tank purely to save any issues.

Better safe than sorry I’ve a 2016 Mk7 golf R also, I’ve removed the pack from the coolant tank just incase 😂

[Topman121]

New Timing belt kit and water pump fitted yesterday, waterpump shield that covers the impeller to allow the car to heat up faster was stuck closed not circulating the coolant properly. New pump has sorted the heating issue now all vents get hot air! 

[dpatel20]

I wanted to add my experience on this topic as it might be useful for others. My issue started very much like the OP - cold air from driver's side and warm(ish) on the passenger side.

 

Skoda Octavia MkIII, 2015.

 

Here's my story:

• I first thought it would be the sensors like the OP and I tried to swap them (they're accessible on either side of the instrument panel --- if you have small hands!). Wasn't that.
• I read about the 'Mit Silikat' issue and saw my coolant looked very much like @centerback had in his pics: browny colour, with small bits in it. If I rubbed the bits between my fingers, they dissolved away so weren't hard lumps. 
• I took it to my local garage and no issues seen through diagnostics (no fault codes, etc and the readings showed vent motors working fine). They flushed the system for me and that helped but not as should be - got luke warm air from both sides.
• I asked the garage to take the 'Mit Silikat' bag out of the expansion tank at the same time as flushing it - the bag did not seem ruptured but I presume the bits in the coolant and the browny colour was due to stuff getting out the bag.
• The heater matrix is located behind the centre console - I took the little trim off the side to expose the matrix pipes so I could keep an eye on them. The trim is held by one screw and just pulls down.
• I drove the car for a couple of weeks. Initially, the in pipe and out pipe of the heater matrix were both very hot (be careful!!) but vent air was luke warm only. So I guessed that the hot coolant was trickling through the matrix (i.e. partially blocked). After a long drive, the air went completely cool on all sides - checked the pipes: in hot, out cool. That confirmed blocked heater matrix for me.
• Had the heater matrix changed - around £320. About half that was the part plus some money for flush & coolant. Rest was labour. Thankfully the heater matrix can be taken out without needing to remove the whole instrument panel so only a couple of hours of labour (no charge for the diagnostics which was nice of them!). There is a video showing how to change the matrix here: https://www.youtube.com/watch?v=Ue7KP4U1xaQ. And if you search for the workshop manuals you should find they explain the same thing - see here: https://www.briskoda.net/forums/topic/461680-mk3-workshop-manual/.
• By the way, there are 2 different manufacturers of the heater matrix for the car (see the workshop manual). My garage were sent the wrong one first time!
• I did not get the expansion tank changed (should do if you want a new 'Mit Silikat' bag). I chose not to have another one of those bags - not advised but it was my choice.
• After that, I've had lovely hot air!

Hope that helps others.

 

[paulski]

21 minutes ago, dpatel20 said:

I wanted to add my experience on this topic as it might be useful for others. My issue started very much like the OP - cold air from driver's side and warm(ish) on the passenger side.

 

Skoda Octavia MkIII, 2015.

 

Here's my story:

• I first thought it would be the sensors like the OP and I tried to swap them (they're accessible on either side of the instrument panel --- if you have small hands!). Wasn't that.
• I read about the 'Mit Silikat' issue and saw my coolant looked very much like @centerback had in his pics: browny colour, with small bits in it. If I rubbed the bits between my fingers, they dissolved away so weren't hard lumps. 
• I took it to my local garage and no issues seen through diagnostics (no fault codes, etc and the readings showed vent motors working fine). They flushed the system for me and that helped but not as should be - got luke warm air from both sides.
• I asked the garage to take the 'Mit Silikat' bag out of the expansion tank at the same time as flushing it - the bag did not seem ruptured but I presume the bits in the coolant and the browny colour was due to stuff getting out the bag.
• The heater matrix is located behind the centre console - I took the little trim off the side to expose the matrix pipes so I could keep an eye on them. The trim is held by one screw and just pulls down.
• I drove the car for a couple of weeks. Initially, the in pipe and out pipe of the heater matrix were both very hot (be careful!!) but vent air was luke warm only. So I guessed that the hot coolant was trickling through the matrix (i.e. partially blocked). After a long drive, the air went completely cool on all sides - checked the pipes: in hot, out cool. That confirmed blocked heater matrix for me.
• Had the heater matrix changed - around £320. About half that was the part plus some money for flush & coolant. Rest was labour. Thankfully the heater matrix can be taken out without needing to remove the whole instrument panel so only a couple of hours of labour (no charge for the diagnostics which was nice of them!). There is a video showing how to change the matrix here: https://www.youtube.com/watch?v=Ue7KP4U1xaQ. And if you search for the workshop manuals you should find they explain the same thing - see here: https://www.briskoda.net/forums/topic/461680-mk3-workshop-manual/.
• By the way, there are 2 different manufacturers of the heater matrix for the car (see the workshop manual). My garage were sent the wrong one first time!
• I did not get the expansion tank changed (should do if you want a new 'Mit Silikat' bag). I chose not to have another one of those bags - not advised but it was my choice.
• After that, I've had lovely hot air!

Hope that helps 

Appreciate you posting clear and concise conclusion to this issue.

 

Good idea in removing the trim to monitor heat in and out of pipes to the heater matrix.

 

Mine decided to give me colder air on drivers side about a week after a routine cambelt change.

 

Cannot fault the garage for a known issue so took it back to them and they flushed it out twice hot and changed the coolant tank upon my request. It's alot warmer than it was before so I'm monitoring it for now. It's handy that the matrix can come out fairly easily. And thanks for giving us the cost you paid. 

 

Enjoy the warm cabin. 

Edited 12 December, 2020 by paulski

[NikTheGeek]

I don't get the brown residue and the silica. Silica is clear and reasonably inert so if the bag ruptures and blocks the heater matrix, I don't understand the sludge in the expansion tank. It's not like the coolant stains the silica otherwise when you remove the bag it would be all brown and horid, but after 5 years the crystals in my bag were all still nice and clear. Are we sure the 2 things are the same and not sand residue left over from the casting process?

[xman]

Its a silicate not silica.

 

 

[dpatel20]

@NikTheGeek

Hard to say to be honest...my bag was not split, so not sure how the silicate was getting out (perhaps there was a small hole...I didn't see the bag after the mechanic took it out but he said it was not obviously split). That said, if it was left over sand from casting, then I would expect it to take a lot less time to become an issue. My car is at ~77K miles and I would have expected sand that was there from day one to cause an issue much sooner.

 

The bits I took out of my expansion tank didn't feel like sand either.

 

And, what I've read from other threads, the bags were clearly split.

 

I have read about silicate gelation caused by having silicate in coolant systems. What I understand, silicate is used to reduce corrosion particularly in the aluminium components. But with that you risk silicate gelation. There is some info here: https://www.jstor.org/stable/44743009?seq=1 (you can read the preview to give you an idea).

 

And this basically says that silicate gelation can block radiators, etc: https://www.frontierpower.com/service/use-low-silicate-antifreeze-heavy-duty-diesel-engines/

 

In my case, I think I had silicate gelation even though the bag did not split. The silicate works by coating the surfaces of the components to protect them...this can then gel up causing blockage (my interpretation/understanding of what happened in my car).

[NikTheGeek]

1 hour ago, xman said:

Its a silicate not silica.

 

 

Silica is a silicate. But either way, the silica (or silicate) in the bag in the expansion tank is clear and remains clear after 5 years of immersion in coolant. Silica (and silicates) are very stable and don't react easily with other chemicals and are unlikely to break down in to a brown sandy mess in the expansion tank.

[NikTheGeek]

1 hour ago, dpatel20 said:

@NikTheGeek

Hard to say to be honest...my bag was not split, so not sure how the silicate was getting out (perhaps there was a small hole...I didn't see the bag after the mechanic took it out but he said it was not obviously split). That said, if it was left over sand from casting, then I would expect it to take a lot less time to become an issue. My car is at ~77K miles and I would have expected sand that was there from day one to cause an issue much sooner.

 

The bits I took out of my expansion tank didn't feel like sand either.

 

And, what I've read from other threads, the bags were clearly split.

 

I have read about silicate gelation caused by having silicate in coolant systems. What I understand, silicate is used to reduce corrosion particularly in the aluminium components. But with that you risk silicate gelation. There is some info here: https://www.jstor.org/stable/44743009?seq=1 (you can read the preview to give you an idea).

 

And this basically says that silicate gelation can block radiators, etc: https://www.frontierpower.com/service/use-low-silicate-antifreeze-heavy-duty-diesel-engines/

 

In my case, I think I had silicate gelation even though the bag did not split. The silicate works by coating the surfaces of the components to protect them...this can then gel up causing blockage (my interpretation/understanding of what happened in my car).

 

This was my bag, freshly removed and not cleaned or rinsed.  It is still full and shows no signs that any of the contents have leached or dissolved in the 5 years it has been immersed in the coolant. So I'm still sceptical. That said, I'm not a chemist and I don't know what variant of silicate they use. Maybe it acts as a catalyst for some other reaction that occurs. Interesting nonetheless.

[shyVRS245]

16 minutes ago, NikTheGeek said:

 

This was my bag, freshly removed and not cleaned or rinsed.  It is still full and shows no signs that any of the contents have leached or dissolved in the 5 years it has been immersed in the coolant. So I'm still sceptical. That said, I'm not a chemist and I don't know what variant of silicate they use. Maybe it acts as a catalyst for some other reaction that occurs. Interesting nonetheless.

It is probably aluminium silicate which consists of aluminium, oxygen and silicon. It has corrosion preventative properties and when mixed with water it can remove impurities (filtering agent). I worked in a pharmaceutical warehouse for 6 years.

[NikTheGeek]

24 minutes ago, shyVRS245 said:

It is probably aluminium silicate which consists of aluminium, oxygen and silicon. It has corrosion preventative properties and when mixed with water it can remove impurities (filtering agent). I worked in a pharmaceutical warehouse for 6 years.

Good call.

 

But would it breakdown to a brown sandy mush/gell? I don't think it would and as you can see from my bag, there is no evidence of it doing so and my expansion bottle was nice and clean. So I'm not sure the silicate bag can be blamed for the sludge people are seeing. Sure it can be blamed for bursting and blocking the heater matrix, but not sludge in the expansion tank.

[shyVRS245]

On the failing water pump thread someone just made a very good point that some diesel engines were assembled with some casting sand still in the block and over time this causes a sludge to build up and forces the water pump to fail as it gets clogged up.

[skodavia]

The coolant pipes enter and exit the matrix at the n/s so this is why when they partially block there is only heat from the passenger side. as the water will flow through only half of the matrix (drivers side blocked more than passenger side) I have posted a guide on this in the guides section. It explains how to do the matrix and costs involved. I will be flushing mine again in the new year as i'm sure there will be more contaminant in there that didn't come out when i flushed mine.