Heating only blowing cold air

Feb 20, 2023
5
1
Hi

I’ve got a 2014 FR Touring, 2L Diesel.

Since I’ve owned the car (6 months) I’ve had the issue where all blowers in the front and rear only blow cold. Similar issue to a chap on a previous thread whereby I get warm air for 5-10 minutes then ice cold. Tried turning the cold/ hot dial for 2 mins at a time as suggested to no avail.

Took to Halfords who said it was an electrical issue they couldn’t fix so took it to the local auto electrics firm who hadn’t a clue why this was happening. They’d never heard of it before and even searched the Seat forums with no luck.

They plugged into it with Launch X.431 and received error 1. P171900 Function Restriction Through Engine Control Module

They advised they didn’t know why the cars computer was restricting this function.

Might have to bite the bullet and take into Seat for a further diag. Garage said Seat might be able to stick an update on that might fix but other than that they’ve no clue !

Any advise or knowledge would be greatly appreciated

Thanks!
 

RUM4MO

Active Member
Jun 4, 2008
7,812
989
South Scotland
Have you, using the contents of previous threads concerning this issue, checked the temperature of the hoses going to and returning from the cabin heater matrix - really just to check that coolant flow is not the issue.
 
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Feb 20, 2023
5
1
Have you, using the contents of previous threads concerning this issue, checked the temperature of the hoses going to and returning from the cabin heater matrix - really just to check that coolant flow is not the issue.
Just took the car out for 45 mins so it had plenty of time to warm up. Removed the panel in the footwell passenger side to access the heater matrix, one pipe was cold and the other was next to cold. Would this indicate a blockage somewhere ? Thanks
 

BigJase88

Jase
Apr 20, 2008
3,767
1,069
Just took the car out for 45 mins so it had plenty of time to warm up. Removed the panel in the footwell passenger side to access the heater matrix, one pipe was cold and the other was next to cold. Would this indicate a blockage somewhere ? Thanks
I would say so

Do you have Mit Silikat written on your coolant header reservoir?

Have a look inside the coolant reservoir [obviously when cold] and see if the bag is split that houses the silicate
 
Feb 20, 2023
5
1
I would say so

Do you have Mit Silikat written on your coolant header reservoir?

Have a look inside the coolant reservoir [obviously when cold] and see if the bag is split that houses the silicate
Yes the coolant reservoir says Mit Silikat on the front. Can’t see a bag of silicate though. Would this be direct in with the coolant or on as an additional part that feeds into the coolant ? Thanks
 

BigJase88

Jase
Apr 20, 2008
3,767
1,069
Yes the coolant reservoir says Mit Silikat on the front. Can’t see a bag of silicate though. Would this be direct in with the coolant or on as an additional part that feeds into the coolant ? Thanks
The bag of silicone sits in the reservoir tank. There are 2 types. One where the bag is visible. One where the bag is held within the wall of the tank so would be harder to see

I would imagine the bag has split at some point. The car is a 2014 so it's a candidate for a split silicate bag. Maybe someone has removed it previously. However it may still of burst hence the blocked heater matrix.

I would maybe suggest a second opinion and take it to a VAG specialist and get them to check the function of the heater matrix. If it is confirmed as blocked then new matrix and non silicate reservoir tank required
 
Feb 20, 2023
5
1
Ah I see, many thanks for the information and help ! If I get a silicate free tank, would I have to use G12 or G13 coolant or is this irrelevant ? Thanks
 

BillyCool

Active Member
Jan 16, 2020
651
248
Leicestershire, UK
The TDI is also prone to having some casting sand from the engine block getting places it shouldn't in the cooling system. Combined with a split silicant bag, a replacement matrix is usually needed.

As for coolant - there was a discussion about that. My personal preference is to replace my coolant about every 3 years, like we used to do in the good old days! That makes the G12/G13 choice less of an issue. I'm not sure there is a coolant for life (hence the annoying silicant bag). Opie oils suggests G13 and this article explains it quite well:


Hope you get it sorted.
 
Feb 20, 2023
5
1
Ah right, that’s a very odd issue to crop up! I guess the casts were getting worn and the apprentice forgot to check haha! I’ll probably end up getting both the matrix and tank changed. Seen the tanks are fairly cheap and the matrix’s aren’t too dear so might just get them both replaced and blow the lines out to get rid of any residue, THEN we may have lift off.

As for the article, it’s certainly swayed me toward G13 so think that’s the go to.

Much appreciated Brian! Thanks
 
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RUM4MO

Active Member
Jun 4, 2008
7,812
989
South Scotland
After flushing etc, just use G12evo it is said by VW Group to be "long life", it is the current and only coolant that VW Group use in factories, in dealership workshops and parts departments.
 

BigJase88

Jase
Apr 20, 2008
3,767
1,069
Ah right, that’s a very odd issue to crop up! I guess the casts were getting worn and the apprentice forgot to check haha! I’ll probably end up getting both the matrix and tank changed. Seen the tanks are fairly cheap and the matrix’s aren’t too dear so might just get them both replaced and blow the lines out to get rid of any residue, THEN we may have lift off.

As for the article, it’s certainly swayed me toward G13 so think that’s the go to.

Much appreciated Brian! Thanks
You may have to do multiple flushes. The Seat garage that did mine said they done it loads of times.

I even had to go back after a month or so as it partially blocked again. Was a complete nightmare
 

BillyCool

Active Member
Jan 16, 2020
651
248
Leicestershire, UK
Ah right, that’s a very odd issue to crop up! I guess the casts were getting worn and the apprentice forgot to check haha! I’ll probably end up getting both the matrix and tank changed. Seen the tanks are fairly cheap and the matrix’s aren’t too dear so might just get them both replaced and blow the lines out to get rid of any residue, THEN we may have lift off.

As for the article, it’s certainly swayed me toward G13 so think that’s the go to.

Much appreciated Brian! Thanks

The casting sand was apparently to do with just not cleaning the blocks properly post-casting. Like you say, a bit weird given the high-tech nature of car production.

I bought a like for like Valeo matrix for mine for €90 from autodoc or similar. Took me less than 3 hours to change with some faffing using the You Tube access via the footwell method. SEAT charge about £1200 (their service doc involves full dash removal) and someone got theirs's done at local garage for £400 or so I think. Header tank was £25 when I got mine but they do seem to have gone up in price.

I happened to have my water pump changed around the same time (another VAG failure point), so I had the mechanic drop the rad hose and ditch as much coolant as possible.

Although the coolant system is a bit complex, I never had the system bled professionally. You can't just blow the lines out, as they have various one way valves and need special VAG kit to fully bleed the system in the correct order (or so they tell you). I've not had any issues after 3 years, although I know others have had a few post-fix problems.

My car is due a full service soon, so I may well get them to do a coolant change, just to keep on top of it.

Let us know how you get on.
 

RUM4MO

Active Member
Jun 4, 2008
7,812
989
South Scotland
Ah right, that’s a very odd issue to crop up! I guess the casts were getting worn and the apprentice forgot to check haha! I’ll probably end up getting both the matrix and tank changed. Seen the tanks are fairly cheap and the matrix’s aren’t too dear so might just get them both replaced and blow the lines out to get rid of any residue, THEN we may have lift off.

As for the article, it’s certainly swayed me toward G13 so think that’s the go to.

Much appreciated Brian! Thanks
As far as I can see, that linked article predates G12evo, I'm running away from G13 ASAP, as have VW Group, in certain engines, like ones that cause create short periods of higher than normal coolant temperature, G13 without getting additional silicate dosed into the solution, fails to maintain its required ph value in service, and so turns acidic, that, I think, is the very reason that only certain VW Group engine types, required these silicate dosing crystal pouches while other VW Group types did not. My wife's 2015 VW Polo 1.2TSI 110PS did not leave the factory with a silicate pouch as presumably that engine type does not typically frequently experience high coolant temperatures, but as time goes on, its G13 coolant is heading towards being acidic a lot quicker than the G12+/G12++ that is in my 2011 Audi S4. Now, consider this, when all engines had cam belts that were replaced at 5 years and frequently also needed water pump replacements, using G13 was not going to be a problem, when some engines came along with cam chain drives and others had long life cam belts - and water pumps that are not connected to the timing belt/chain, the likelihood of the coolant, which is listed as being longlife, getting replaced on a "regular" basis, has suddenly vanished, so for these cars that have/had engines that actually "needed" this silicate dosing - meant that just removing these essential for these cars, silicate pouches, became not so good an idea overall, okay some people say "just replace the coolant frequently" - but what about the many people that don't know or consider getting that extra work done? For my money, the change from G13 to G12evo, so far, just makes so much sense.

Any/every aftermarket supplier of coolant that conforms to G13 inform you that it needs replaced every 3 or 4 or 5 years - they know their product's limitations in certain engines, so hand out that recommendation. In time they will also, like VW Group and others, I'd think, move on and so to offering only G12evo equivalent coolant for these cars.