Heaters blowing warm

[Deano3]

Hi everyone hope you are all well, i had my car in for timimg belt and water pump etc in november and not really used much since due to whats going on, i have recently noticed my heaters arent really getting hot when on full blast just warm and i am not sure if cooling sysyem needs bleeding , just wondering how i go about this ?

The coolant reservoir is on correct level and temp stays at 90 and doesnt go any higher, i tried squeezing some of the pipes ontop but still the same, is it hard to check pipes into the heater matrix as i imagone it is buried in the dash ?

Any help appreciated
Thanks dean

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[BoomerBoom]

Common faults are air control flap or the heater matrix is blocked. If it's diesel and you have the silica gel pack in the coolant reservoir then the matrix is most likely, but you can easily check the flap control by checking if all the vents give the same temperature - both on full heat and full aircon. If one side is hotter, or cooler, than the other then it's the flaps.

Both issues have more detailed threads on the solutions, so probably better to search for those.

If it's petrol and the flaps are okay then it would be worth taking back to the same garage and putting the problem to them, asking if an air lock could remain.

 

[Deano3]

Common faults are air control flap or the heater matrix is blocked. If it's diesel and you have the silica gel pack in the coolant reservoir then the matrix is most likely, but you can easily check the flap control by checking if all the vents give the same temperature - both on full heat and full aircon. If one side is hotter, or cooler, than the other then it's the flaps.

Both issues have more detailed threads on the solutions, so probably better to search for those.

If it's petrol and the flaps are okay then it would be worth taking back to the same garage and putting the problem to them, asking if an air lock could remain.

Thanks for that, it is a diesel 150 fr model and i did notice yeaterday the passenger side seemed hotter than driver side even when sync on and temp at full.

Is there anything you can do with the flaps to maybe reset or anything?

Thanks dean

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[BoomerBoom]

Not as far as I know, sorry.

 

[SuperV8]

Thanks for that, it is a diesel 150 fr model and i did notice yeaterday the passenger side seemed hotter than driver side even when sync on and temp at full.

Is there anything you can do with the flaps to maybe reset or anything?

Thanks dean

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You can re-set/calibrate flaps via some (better) diagnostics interfaces.
I suggest if you put the temp setting on cold and it goes cold, and on hot it goes hot-ish then I would be looking at other faults first, especially as it was hot before the timing belt change.

Lower temperature on drives side vs passenger side (UK cars) is a known heater matrix issue, as the matrix partially blocks the drivers side surface first. Loads of threads on here. Either silica remains from sand casting process, silica from split Mit-silica bag in header tanks, or just a build up of flakes/junk in the cooling system, which blocks the small passageways of the heater matrix.

I also did my timing belt a few weeks ago - and I flushed/vacuum bleed my coolant system as well. I did feel that following this my hi-heat wasn't quite a toasty as before. You can see the heater matrix pipes in the engine bay behind the engine, and can just about reach them. I tried squeezing mine to try and release a possible air pocket, but anyway after several cold start drives/days I noticed on one journey it went nice a toasty. The cooling system is very complicated with lots of possibility of trapped air - dealers are even supposed to run a diagnostic procedure after vacuum filling the cooling system.

So I would say it could be trapped air and/or blocked heater matrix.

Tom.

 

[Deano3]

You can re-set/calibrate flaps via some (better) diagnostics interfaces.
I suggest if you put the temp setting on cold and it goes cold, and on hot it goes hot-ish then I would be looking at other faults first, especially as it was hot before the timing belt change.

Lower temperature on drives side vs passenger side (UK cars) is a known heater matrix issue, as the matrix partially blocks the drivers side surface first. Loads of threads on here. Either silica remains from sand casting process, silica from split Mit-silica bag in header tanks, or just a build up of flakes/junk in the cooling system, which blocks the small passageways of the heater matrix.

I also did my timing belt a few weeks ago - and I flushed/vacuum bleed my coolant system as well. I did feel that following this my hi-heat wasn't quite a toasty as before. You can see the heater matrix pipes in the engine bay behind the engine, and can just about reach them. I tried squeezing mine to try and release a possible air pocket, but anyway after several cold start drives/days I noticed on one journey it went nice a toasty. The cooling system is very complicated with lots of possibility of trapped air - dealers are even supposed to run a diagnostic procedure after vacuum filling the cooling system.

So I would say it could be trapped air and/or blocked heater matrix.

Tom.

Thanks for that tom, i seen online people holding the A/C button and the middle heater position button to reset the hvac sysyem and that seemed to improve it a bit but still slightly hotter on the passenger side.

Is there anyway to remove the silica bags from the resivoir to stop this from happening if hasnt alreay ?

I need to give it a good hour or more run out to see if improves anything.

Thanks again dean

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[BillyCool]

Thanks for that tom, i seen online people holding the A/C button and the middle heater position button to reset the hvac sysyem and that seemed to improve it a bit but still slightly hotter on the passenger side.

Is there anyway to remove the silica bags from the resivoir to stop this from happening if hasnt alreay ?

I need to give it a good hour or more run out to see if improves anything.

Thanks again dean

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As others have said, it could be an air lock as bleeding the 3 coolant circuits is quite an involved job, although the system is supposed to self-bleed to an extent.

Several of us have experienced a blocked heater matrix and it seems very common with TDI's.

This thread covers a lot of it.

HELP ME PLEASE!!!

Hi guys, I have a 2014 Leon FR (mk3). I need to remove the heater matrix. I’ve been advised that this can be done without removing the dashboard. Is this true? Apparently it can be accessed and removed from the passenger footwell area. Any advice please guys?

www.seatcupra.net

Ref the expansion tank. I replaced mine to one without a silcant bag - only way to ensure it didn't have one. As for your car, the damage is probably already done. You can actually get to the matrix pipes via the passenger footwell if you take one panel off. The video in the above thread covers that (You Tube Video).

I replaced my own matrix for €80 and 3 hours of my time rather than the £1200 that SEAT wanted. Someone got it done at an Indie for about £300 I think.

It can be heater flaps and apparently with VCDS you can test them. Never actually found someone who had that issue though. It was always the matrix.

 

[SuperV8]

Thanks for that tom, i seen online people holding the A/C button and the middle heater position button to reset the hvac sysyem and that seemed to improve it a bit but still slightly hotter on the passenger side.

Is there anyway to remove the silica bags from the resivoir to stop this from happening if hasnt alreay ?

I need to give it a good hour or more run out to see if improves anything.

Thanks again dean

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Ah - every day's a school day - didn't know about that reset procedure, thanks for sharing.

From what I can see there are three types of header coolant tanks used and it depends on what type you have.

The older type with Mit-Silicate marking on the side of the header tank has a 'tea bag' like silicate bag visible from inside the neck of the tank. this is the type which can be carefully removed with needle nose pliers.

The newer type (which my 2015 Leon had) has Mit-silicate marking BUT is it not visible, the silicate repository is not removable on this type and is contained within the tank, the coolant return flows through this repository. I brought a new tank WITHOUT silicate. I'm not sure if this type actually leaks silicate granules, but it's simple/cheap insurance plus you get a nice clean header tank, they are only arround £20. Just make sure you change the coolant every 4 to 5 years - which you need to do anytime you do a timing belt anyway!

The latest genuine VW header tank does not contain a silicate repository.

 

[Deano3]

Thanks for the help i will have a bit investigation when next off as got the van all week at work. Yeah that procedure i mentioned you can hear the flaps working and resetting so hopefully gets better but i will find out what header tank i have and go from there.

Thanks again
Dean

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