I have a 63 plate Octavia 1.6TDI with just over 50,000 miles on the clock and the heater matrix has corroded such that it has blocked after being flushed twice. Is going into a specialist garage to have the matrix changed and wondered if anyone else has had this problem? Mechanic said never seen it on such a new car but a call to his mate at a VW garage has shown that a few Passats are coming in with this problem. Had been Skoda serviced from new!

Andy

Hi,

 

I have a 2014 1.6 tdi with 36000 miles - heater stopped blowing hot air two weeks ago. I have just been told the matrix is blocked and that it needs to be replaced. You’re not alone.

looks like this might be the next issue to develop for the O3......

Thanks Dalbeathie. The mechanic that changed the matrix on my car did not know what the underlying problem was that caused the matrix to block so I imagine it will do the same again in time. Let me know if your mechanic has any idea of the cause and possible prevention!

Out of interest / for future reference, how much does it cost to change the heater matrix?

Mmm, mine was flushed to start with which only lasted a couple of weeks and then the matrix was replaced... £700 in total...bargain !!! 

It is normally due to there being not enough 'antifreeze' in the coolant. Many think that just because it is not freezing they don't need it. Most have strong inhibitors in to stop rust and scale. With just pure water, especially tap water, the engine generates quite a lot of crap quite quickly.

 

Those 'leak-fix' type fluids like radweld have also caused problems in heater matrix too.

 

If the car had been only dealer serviced I would be having words

Thanks Flybynite, I have made an assumption that dealers would only top up with approved coolant of course! I do wonder if it might be something else though, as a few cars are now reporting this with quite low mileage?

Many years ago Vauxhall’s had this issue. It will be a design/manufacturing fault with the matrix. I changed loads of heater matrixs as an apprentice mechanic at a Vauxhall dealer. The good thing was they were designed to be replaced relatively easily without removing the entire dashboard. I guess for 700 quid this isn’t the case with the Octavia.

Yep, I suspect a manufacturing or design fault as well and yes you are quite right it was a dashboard out job on the Octavia!

The ones I used to see were leaking, rather than blocking up but I seem to recall it was caused by electrolysis removing metal from within the core of the matrix. In those days Omegas and Senators used to fail a lot more than the other models even though all the matrixs looked similar to me. 

There is some scientific explanation that somehow electric current can pass through the coolant and affect the matrix, I’m sure somebody cleverer than me will know !

Edited 8 December, 20178 yr by classic

Skoda UK should be paying for these, out of warranty or not, no MkIII Octavia should be suffering from heater matrix failure.

 

It's pretty difficult to argue fair wear and tear, if it has a full dealer service history they can't argue you've topped it up with water either.

 

Don't roll over guys, dig in and push hard for an FOC replacement...

 

http://www.skoda.co.uk/about-us/contact-us

You are correct silver - I’m not happy. Mines is only 36000 miles and I drive it like the boring old fart I am. I have emailed them and will let you know what they say. Thanks for the prompt!

On 07/12/2017 at 17:25, SkodaAndy said:

Thanks Dalbeathie. The mechanic that changed the matrix on my car did not know what the underlying problem was that caused the matrix to block so I imagine it will do the same again in time. Let me know if your mechanic has any idea of the cause and possible prevention!

 

On 07/12/2017 at 17:25, SkodaAndy said:

Thanks Dalbeathie. The mechanic that changed the matrix on my car did not know what the underlying problem was that caused the matrix to block so I imagine it will do the same again in time. Let me know if your mechanic has any idea of the cause and possible prevention!

Hi Andy, he thought Radweld had been put into the cooling system which simply isn’t the case. I suspect it might be corrosion for reasons I don’t understand. I have sent Skoda a moaning email.

Look like this may be the next common issue and not a cheap or easy job either. Things that need to be noted by owners.

1: Has the concentration of G13+ been maintained at the correct level.

2: Has anyone added coolant other than G13+ Some motor factors state their own brand coolant is compatible, but it isn't. It must be G13+

3: Obviously stuff like radweld should never be added.

4: Have any users with the problem, topped up the coolant with tap water from a region that is classed as having 'hard' water. Use only distilled water.

 

If the coolant in the header tank is clean and the heater matrix is blocked then there has to be some kind of chemical reaction going on and if all of the Skoda instructions have been followed regarding topping up, then that would mean a clear manufacturing defect. EU law would state, that units failing in a relatively short time frame are not fit for purpose.

 

10 minutes ago, MoggyTech said:

Look like this may be the next common issue and not a cheap or easy job either. Things that need to be noted by owners.

1: Has the concentration of G13+ been maintained at the correct level.

2: Has anyone added coolant other than G13+ Some motor factors state their own brand coolant is compatible, but it isn't. It must be G13+

3: Obviously stuff like radweld should never be added.

4: Have any users with the problem, topped up the coolant with tap water from a region that is classed as having 'hard' water. Use only distilled water.

 

If the coolant in the header tank is clean and the heater matrix is blocked then there has to be some kind of chemical reaction going on and if all of the Skoda instructions have been followed regarding topping up, then that would mean a clear manufacturing defect. EU law would state, that units failing in a relatively short time frame are not fit for purpose.

 

 

Thanks all. I noticed the problem when the coolant low light came on and then topped up with G13.  The base of the expansion vessel was mucky and rust coloured. Then noticed some time later no hot air blowing in to car, but as it was summer suspect this may have been the case for some time. First garage blew through the matrix and said chunks of corrosion came out! Lasted a couple of weeks before blocking again. Second garage did the same and found the same...lasted a week and then replaced matrix saying could barely blow through it was so blocked. Had to go back for a number of flushes as system was so dirty, turning the bright pink coolant to mucky  brown.  Think I may need to go back again as browning up again and starting to lose a bit of coolant again!

1 hour ago, SkodaAndy said:

Thanks all. I noticed the problem when the coolant low light came on and then topped up with G13.  The base of the expansion vessel was mucky and rust coloured. Then noticed some time later no hot air blowing in to car, but as it was summer suspect this may have been the case for some time. First garage blew through the matrix and said chunks of corrosion came out! Lasted a couple of weeks before blocking again. Second garage did the same and found the same...lasted a week and then replaced matrix saying could barely blow through it was so blocked. Had to go back for a number of flushes as system was so dirty, turning the bright pink coolant to mucky  brown.  Think I may need to go back again as browning up again and starting to lose a bit of coolant again!

Just noticed this is affecting diesel engines which use an iron engine block. If fresh coolant is turning rusty coloured, that would suggest engine block corrosion. Given that G13 coolant is meant to have corrosion inhibitors, are they working?

This ones got me a bit stumped. I had a 1.9 Fabia VRS LE for years, and it never had these kind of issues.

MoggyTech, I think you may be on the money with engine block corrosion. The coolant looks just like some something iron based is corroding some where in the system.  I made the assumption that it was the matrix as that was what blocked, also thought maybe the radiator? Either way the inhibitors in the coolant don't appear to be effective. I have sent a moan to Skoda to see if they come back with anything!

2 hours ago, SkodaAndy said:

MoggyTech, I think you may be on the money with engine block corrosion. The coolant looks just like some something iron based is corroding some where in the system.  I made the assumption that it was the matrix as that was what blocked, also thought maybe the radiator? Either way the inhibitors in the coolant don't appear to be effective. I have sent a moan to Skoda to see if they come back with anything!

The radiator and heater matrix are alloy so any rust coloured crud in the coolant has to be from the engine block water passages. My Fabia VRS used G11 coolant (Glycol based) and G13 is glycerine based, not sure if the switch by Skoda is having an effect on cast iron engine blocks, but something must be causing the corrosion. 

 

Top tip for anyone wanting free clean top up water free from normal tap water impurities, keep the water from your fridge freezer after defrosting. 

Hi SkodaAndy, did you ever get anywhere with your complaint to Skoda about this?  I think I have an identical car (Octavia Mk III, 13 plate, 1.6TDi, 56,000 miles) and my heater matrix is apparently also corroded and blocked.  Main dealer want £1,400 to replace that and secondary coolant pumps.  They can't explain the cause.  My coolant is also a mucky brown colour and looks thick as treacle when cold.  Cam belt and main water pump was changed by main dealer in the summer and I can't help thinking there's a connection there somewhere.  Any tips on complaining to Skoda are gratefully received!  Thanks.

Sounds like the silica bag has burst and blocked the heater matrix. If you look for with words "mit silikat" on the filler tank to see if you have one.

Its a known fault on the octy 3 where this type of system is fitted depending on th engine.

21 hours ago, 3rdoctavia said:

Sounds like the silica bag has burst and blocked the heater matrix. If you look for with words "mit silikat" on the filler tank to see if you have one.

Its a known fault on the octy 3 where this type of system is fitted depending on th engine.

 

Lots of this issue reported on Golf forums, some have had them replaced under warranty but only a few.

I had mine changed last month due to no heating and brown coolant. They changed the heater matrix, coolant reservoir and flushed the system a load of times.  It was all covered under the approved used warranty without any quibbles which was great.

Thanks all.  I've owned the car since new so sadly have no warranty now to fall back on 😫