Hi, 

 

I'm new here, having recently bought a new-to-me 16 plate Scout. I'm not new to Skoda, though - I had a mk 1 Octavia SLX tdi estate from 1999 to 2008, and it remains one of the most reliable cars I ever owned...

 

I'm sorting through a few issues on the car and discovered that I have the dreaded sludgy coolant / blocked heater matrix issue. Currently weighing up options. 

 

I found this alternative heater matrix: http://www.motoradsonline.co.uk/products/Skoda-Octavia-Heater-matrix-2013-onwards.html . Has anyone had any luck using one? On the face of it, the larger coolant passages sound like a good idea. 

 

My main concern is whether adding a brass / copper component into the cooling system is going to mess with the coolant chemistry. Does anyone have any insight into this?

 

Thanks!

I don't think the blocked heater matrix is a design issue, instead it's a symptom of having contaminants in the cooling system

 

There is a Skoda TPI for this issue 2050019/13 so depending where/how you bought your car, you might be able to get this covered under warranty?
 

Quote

 

Customer statement:
• Coolant reservoir is contaminated/coloured; and/or
• Deposits are visible in the coolant reservoir; and/or
• Insufficient heating performance in the vehicle interior.
 

Workshop findings:
• Coolant is contaminated/coloured; and/or
• Deposits in the coolant reservoir or in the whole cooling system; and/or
• Insufficient heating performance in the vehicle interior, hoses leading to heat exchanger are cold.

 

Technical background
• Premature ageing of coolant caused by heat overload; and/or
• Using coolant with low or too high concentration (causing corrosion or heat overload of the cooling system); and/or
• Operating the vehicle with a coolant not complying with the prescribed quality requirements (see Owner’s Manual / Workshop Manual); and/or
• Remnants from production in the cooling system contaminate this system or clog the heat exchanger of the heating.

 

 

If it were my car, I'd probably try the cleaning routine and see if that unblocks the heater matrix. If it doesn't, I'd probably change like for like and then running the cleaning routine again.

 

While switching for a larger bore heater matrix might help prevent it from blocking, having contaminants in the cooling system will still effect the performance and longevity of various components...

 

 

A quick google suggest G13 might not work well with brass/copper/soldered radiators although G12evo might be fine? I'd definitely suggest double checking that... 

 

1 minute ago, langers2k said:

I don't think the blocked heater matrix is a design issue, instead it's a symptom of having contaminants in the cooling system

Thanks for the reply!

 

Yes, I get that. I don't understand what's caused the contamination. I've read a lot about the silicate additive (which my car has), but Skoda don't seem to reference this in their TPI. Can't see why it would have overheated (or why so many people, with different engines on different VAG cars using the MQB platform, have had the same problems). Maybe they're acknowledging that a lot of cars had casting residue in the system?

I fully intend to make sure the whole system is properly clean anyway, before doing anything else.

Having done a little more research online, I'm fairly sure that adding brass / copper / solder into the coolant circuit is likely to be a bad idea in the long run, so I'm more likely to stick with a like-for-like replacement.

The car has a goodwill warranty from the (independent) dealer I bought it from, and he's been very helpful and responsive so far and indicated that he'll sort it, one way or the other. It's booked in at the local Skoda dealer for them to have a look, so I'll wait to see what they say. 

1 hour ago, Snapperseb said:

Hi, 

 

I'm new here, having recently bought a new-to-me 16 plate Scout. I'm not new to Skoda, though - I had a mk 1 Octavia SLX tdi estate from 1999 to 2008, and it remains one of the most reliable cars I ever owned...

 

I'm sorting through a few issues on the car and discovered that I have the dreaded sludgy coolant / blocked heater matrix issue. Currently weighing up options. 

 

I found this alternative heater matrix: http://www.motoradsonline.co.uk/products/Skoda-Octavia-Heater-matrix-2013-onwards.html . Has anyone had any luck using one? On the face of it, the larger coolant passages sound like a good idea. 

 

My main concern is whether adding a brass / copper component into the cooling system is going to mess with the coolant chemistry. Does anyone have any insight into this?

 

Thanks!

As you have a TDI, this thread may be relevant to you. The gist is that sometimes casting sand/sludge/debris can block the heater matrix, it's not always due to a silica bag failure.

I've linked to start at the appropriate post.

As for replacing OEM with alternative bits, I'd get some expert advice on that, but my gut instinct is to reject the idea, as it introduces another unknown variable into the problem. But that's just my opinion.

@Snapperseb Congrats about your new purchase for a 2016 Scout.  Hopefully you might be able to send us a photo of it when you ready.

 

Ref: cooling system.  Sounds like the silica bag has burst and it has blocked the heater matrix.  At least it is a known issue - and the others are right - there is a TPI associated with this.  Most of us in the know tend to remove the silica teabag from the coolant header tank. 

2 hours ago, Snapperseb said:

My main concern is whether adding a brass / copper component into the cooling system is going to mess with the coolant chemistry

If you have the silica teabag in the header tank, the silica and the ready mixed G12++/G12evo/G13 cooland should protect those metalic components mentioned.

 

So - when your Scout is back to health, you just need to remember that the coolant will need changing every 5 years.

 

 

1 hour ago, EnterName said:

As you have a TDI, this thread may be relevant to you. The gist is that sometimes casting sand/sludge/debris can block the heater matrix, it's not always due to a silica bag failure.

I've linked to start at the appropriate post.

As for replacing OEM with alternative bits, I'd get some expert advice on that, but my gut instinct is to reject the idea, as it introduces another unknown variable into the problem. But that's just my opinion.

 

Thanks, I saw that thread. I'm not sure it's particularly reassuring!

I think I agree with you on non-OEM. My other vehicle is a heavily modified VW T3 pickup running a Subaru engine, so I'm used to mixing and matching components. But on a modern car I'm much less keen.

1 hour ago, varaderoguy said:

 

when your Scout is back to health, you just need to remember that the coolant will need changing every 5 years.

 

 

Yes, I'd be doing that anyway every 4 years with a belt and pump change anyway  Very much not a fan of 'for life' fluid fills. They never are, and they always cause some kind of problem down the line...

For the record, when removing my silicate bag from my reservoir, there were orange deposits "limescale" coating the inside of the reservoir. On having my water pump changed, these same orange deposits were sticking the sleeve shut (I asked for the pump back).

The coolant will be changed every 1-2 years, so no more need for silicate bags!

Edited 27 August, 20214 yr by micro

I think there is a revision B matrix with slightly wider channels - reading the below thread related to the golf lead me to change mine with a part number quoted somewhere in the comments. 

 

https://forums.tdiclub.com/index.php?threads/coolant-blown-out-from-expansion-bottle.483783/

 

Apologies if we're not allowed to link to other forums - please delete link if needed. 

 

I've not had any issues since replacement. I thought my car was solved. Then it had a coolant flush/replacement and after collecting the car, no heat (I've discussed on here my previous problems with the coolant debris issue).

 

I had the replacement matrix for ages, sat in a box, so just replaced it and problem solved. Lots of heat, coolant still looks as it did when replaced, happy owner.