Duel climate heating only heating passenger side.

[hewittinspain]

Ive noticed today that the drivers side of the heating stays cool on my 14 plate FR, but on the passenger side it can be controlled properly. Having said that even on high temperature the passenger side isn't as hot as it seemed to be before but its still ok.
Ive tried turning the engine on and off, playing around with the controls from (cool to hot), turning on/off sync but the drivers side is still blowing coolish air out.

What possible issues are there and at what cost? Is there anything I can try that I havent already?

 

[BillyCool]

What model is it? Is it a TDI?

 

[hewittinspain]

What model is it? Is it a TDI?

Its the FR model

 

[BillyCool]

I have the 2104 184 FR TDI and the diesels have a known issue with the heater matrix getting blocked. One of the signs is limited/reduced heating in the cabin, moreso on the drivers side. It usually leads to coolant loss during DPF regens as well.

There can also be other issues with the heater control actuators (the motorised flaps) in the dash or faulty temp sensors in the heating vents.

Have you had any issues or work done on the matrix?

 

[hewittinspain]

What model is it? Is it a TDI?

Yes its diesel

 

[hewittinspain]

I have the 2104 184 FR TDI and the diesels have a known issue with the heater matrix getting blocked. One of the signs is limited/reduced heating in the cabin, moreso on the drivers side. It usually leads to coolant loss during DPF regens as well.

There can also be other issues with the heater control actuators (the motorised flaps) in the dash or faulty temp sensors in the heating vents.

Have you had any issues or work done on the matrix?

Not that im aware of no. I had a recent service three weeks ago on the car, could anything have been knocked accidentally? Is there anything I can have a check on? How would a mechanic figure out the issue if its the matrix or something else?

 

[BillyCool]

Well - if you let a garage anywhere near your heater matrix, it will cost a lot to fix or even try and fault find.

SEAT quote about £1200 to change the heater matrix. You can buy one yourself for €80 and about 2 hours of your time (and some tools and patience) to can do it yourself. You can test it by checking the in/out pipes for the matrix. In should be hot and out should be warm (heating on full). You can try to feel the pipes on the bulkhead (in the engine bay) or take a panel off in the footwell to directly access the pipes into the matrix. The general idea is that a blocked matrix makes both pipes very hot (it did on mine). Not sure exactly how a garage would test it but I'm sure it would cost £££'s.

In terms of the actuators and temp senders, you can get someone with VCDS to check the voltages on the actuators/motors (make sure they are working properly) and check that the temp senders are both accurately reporting the air vent temps.

A service wouldn't pick up on anything like that and I'm not sure that a service would/should influence anything like that but I'm not sure.

Was the heating working okay before it went for service or you've just not been using it and only just noticed it's not working correctly?

 

[hewittinspain]

Well - if you let a garage anywhere near your heater matrix, it will cost a lot to fix or even try and fault find.

SEAT quote about £1200 to change the heater matrix. You can buy one yourself for €80 and about 2 hours of your time (and some tools and patience) to can do it yourself. You can test it by checking the in/out pipes for the matrix. In should be hot and out should be warm (heating on full). You can try to feel the pipes on the bulkhead (in the engine bay) or take a panel off in the footwell to directly access the pipes into the matrix. The general idea is that a blocked matrix makes both pipes very hot (it did on mine). Not sure exactly how a garage would test it but I'm sure it would cost £££'s.

In terms of the actuators and temp senders, you can get someone with VCDS to check the voltages on the actuators/motors (make sure they are working properly) and check that the temp senders are both accurately reporting the air vent temps.

A service wouldn't pick up on anything like that and I'm not sure that a service would/should influence anything like that but I'm not sure.

Was the heating working okay before it went for service or you've just not been using it and only just noticed it's not working correctly?

To be honest I dont think ive had the heating on for a while due to the mild temperatures. It was only because I had my girlfriend in the car and she was cold that I put her side on heat and mine on cool but when I tried to turn my side up a little it stayed on cool.
The mechanic that does my service is a friend of my girlfriend that used to work for VW but now works for Ford. The plan is to wait until I need another service in around 6 months and get him to look at the issue then. Do you think I can do this as long as the passenger side doesn't start going cold or is it an urgent matter? As it is now I can probably cope the winter seeing as one side is still working.
Thats great advise by the way and I can have a look at the pipes in the meantime

 

[BillyCool]

You shouldn't damage anything if you leave it. You just won't get hot air.

Have you ever had to top up the coolant? A tell tale sign of a blocked matrix is that after a DPF regen, the heater matrix is used to cool the EGR cooler and the coolant overheats/boils and exits the system via the escape valve under the cap in the expansion bottle. You don't notice at the time until the car cools down and the coolant level drops. Next time you start the car you get a low coolant warning.

You should be okay to leave it for now but just monitor your coolant levels.

Hopefully, it might be another (simpler) issue.

 

[hewittinspain]

You shouldn't damage anything if you leave it. You just won't get hot air.

Have you ever had to top up the coolant? A tell tale sign of a blocked matrix is that after a DPF regen, the heater matrix is used to cool the EGR cooler and the coolant overheats/boils and exits the system via the escape valve under the cap in the expansion bottle. You don't notice at the time until the car cools down and the coolant level drops. Next time you start the car you get a low coolant warning.

You should be okay to leave it for now but just monitor your coolant levels.

Hopefully, it might be another (simpler) issue.

Ive never checked the coolant levels and had no warning. Maybe I should really keep an eye on those anyway? ?. Im guessing the guy that serviced my car would have checked those

 

[BillyCool]

Ive never checked the coolant levels and had no warning. Maybe I should really keep an eye on those anyway? ?. Im guessing the guy that serviced my car would have checked those

That's okay then. You should get a low coolant warning if it was low and it's really easy to check. It certainly should have been checked at service.

It might not even be your heater matrix or it's partially blocked and not causing DPF regen overheats.

If the car isn't shouting at you, don't worry about it!

 

[hewittinspain]

That's okay then. You should get a low coolant warning if it was low and it's really easy to check. It certainly should have been checked at service.

It might not even be your heater matrix or it's partially blocked and not causing DPF regen overheats.

If the car isn't shouting at you, don't worry about it!

Thanks a lot for your advise. Ive noted everything

 

[Cuprabenwytm]

Blocked matrix possibly, the header tank has this bag inside thats pops over time and blocks it

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[SuperV8]

To be honest I dont think ive had the heating on for a while due to the mild temperatures. It was only because I had my girlfriend in the car and she was cold that I put her side on heat and mine on cool but when I tried to turn my side up a little it stayed on cool.
The mechanic that does my service is a friend of my girlfriend that used to work for VW but now works for Ford. The plan is to wait until I need another service in around 6 months and get him to look at the issue then. Do you think I can do this as long as the passenger side doesn't start going cold or is it an urgent matter? As it is now I can probably cope the winter seeing as one side is still working.
Thats great advise by the way and I can have a look at the pipes in the meantime

I had the same symptoms, and mine turned out to be the heater matrix partially as previously mentioned. Drivers side cold, passengers side hot.
Loads of threads on various forums of VW/Seat/Skoda/Audi/MQB TDi's with this common issue.
I too thought I'd try and live with it (last autumn) until the spring but I my case I had a couple of coolant losses from the header tank, didn't happen when I was driving, just when stopped (it turns out after a DPF regen) it has a ton of heat left in the coolant circuit and with a blocked heater matrix the EGR circuit is also blocked. I would get a coolant low warning on the dash. So keep a bottle of water in the car just in case.
Just to add, I found driving with little heat in the winter - when it gets cold - a rather miserable experience! and i'm not one who ever complains about the cold, or turns the heating up at home!

 

[hewittinspain]

I had the same symptoms, and mine turned out to be the heater matrix partially as previously mentioned. Drivers side cold, passengers side hot.
Loads of threads on various forums of VW/Seat/Skoda/Audi/MQB TDi's with this common issue.
I too thought I'd try and live with it (last autumn) until the spring but I my case I had a couple of coolant losses from the header tank, didn't happen when I was driving, just when stopped (it turns out after a DPF regen) it has a ton of heat left in the coolant circuit and with a blocked heater matrix the EGR circuit is also blocked. I would get a coolant low warning on the dash. So keep a bottle of water in the car just in case.
Just to add, I found driving with little heat in the winter - when it gets cold - a rather miserable experience! and i'm not one who ever complains about the cold, or turns the heating up at home!

Was it an expensive fix? If the matrix is blocked then does it need a new one or can it be unblocked by someone to save money?

 

[BillyCool]

Was it an expensive fix? If the matrix is blocked then does it need a new one or can it be unblocked by someone to save money?

If SEAT quote to replace the matrix it is about £1200. You can buy one for €80 and fit it yourself in a couple of hours. Some people do flush their old matrix out but they are very rarely as good as new.

 

[BigJase88]

Yeah burst silica bag in header tank blocking the heater matrix

just had a new matrix in my A3 (same setup) and i still have issues, going back again this month for a coolant flush as must still be some silica in the system.

poor showing from VAG, own goal

the tell tale sign is the coolant going brown in the expansion tank, will need a new header tank also.

 

[SuperV8]

Yeah burst silica bag in header tank blocking the heater matrix

just had a new matrix in my A3 (same setup) and i still have issues, going back again this month for a coolant flush as must still be some silica in the system.

poor showing from VAG, own goal

the tell tale sign is the coolant going brown in the expansion tank, will need a new header tank also.

Can be the 'Mit Silica' bag split - AND/OR - left over silica/sand from the engine casting production process.
My coolant is still pink/purple - but still blocks the heater matrix.
the trouble with 'just' fitting a new heater matrix is you don't know how much silica is still circulating in the system? The full VAG procedure also includes several cooling system flushes with cleaning solution - sounds like this wasn't done in your case?

 

[SuperV8]

Was it an expensive fix? If the matrix is blocked then does it need a new one or can it be unblocked by someone to save money?

For me it was free as I did it myself. Getting the heater matrix out is quite simple (glove box out, blower motor out, couple small trim panels - and you can pull the matrix out), and then I found the garden hose adapter fits perfectly as in the picture shared so you can back flow some good high pressure/volume water through. I kept doing this until I could see minimal 'silica' in my collection bucket. Now this won't be 'perfect' - but I found it to work well and full heat restored.

To problem is - it depends how much silica you have in circulation in your cooling system? the matrix will act like a filter of your coolant, Mine has blocked up a couple times since so I have flushed the matrix 3x in total now - There is a finite amount of silica in the system so eventually this matrix flushing will be a permanent fix, and now I can flush the matrix in under an hour (total) and its free so I don't mind doing it a couple more times if needed.

I'm doing my cam-belt soon and will also flush my cooling system while i'm at it so hope fully that will be an end to it.

 

[Cuprabenwytm]

Use some mr muscle to get it all out i reac somewhere

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