Leon Heating Only Working On Passenger Side

[vixonss]

Hi all, I've already had a little look around to see if anyone has come into the same issue as me, but I cant seem to find someone with the exact same fault. It is either they heating all together isn't working or their vents are not working.

I've owned the car since Nov 23 and the fault has occurred since then the seller didn't advice me of this it was only brought to my attention when my father had used my car as his had stopped working.

Basically when the car gets to operating temperature the passenger side is nice and warm as it should be however, the driver side is just cold like the air con is on. (the center console vent driver side also doesn't seem to get to speed 6 but i think that is due to a different issue.)

This Leon is a single climate control spec.

I don't believe that the heater matrix is blocked or has died as heat does go to the passenger side. I've thought about flushing the heating system as I've read that a lot of the time there is a little bag in the coolant tank that splits and leave debris in the heater matrix, but I'm unsure on if that would do the trick as it seems to be an issue on delivery to the driver side of the car (I'm not smart when it comes to how car stuff works so all help is appreciated.)

My fathers cousin is a mechanic so he's messaged him today just waiting for a reply I just thought that in the meantime any advice on here would be greatly appreciated.

For context this is a right hand drive car, 1.6TDI engine that has clocked just under 170k miles.

 

[SuperV8]

A blocked heater matrix can indeed cause your symptoms of heating only on the passenger side.
The heater matrix area is divided; half of the matrix area goes to the passenger side, the other half goes to the drivers side - when blocked, only part of the matrix gets hot, and this is the part which goes to the passenger side.
Many posts on here about blocked heater matrix with TDI's.
Simple to change - from the passenger footwell, remove a few lower trim panels, glove box and blower motor - and the matrix can be pulled out and exchanged. Have a tray ready to collect less than 500ml coolant - no need to disconnect hoses in the engine bay.
Best to do a coolant flush - BEFORE fitting your new matrix.

 

[vixonss]

Thanks for the reply V8, I was thinking of just getting the matrix flushed but if the matrix is the problem they seem fairly cheap to purchase now like £40 for a brand new one so I’ll order a matrix today in hopes that it will be here before the weekend.

I also have a question in regards to the coolant tank, apparently there’s a problem with the tank disintegrating or something if the sorts and debris gets into the matrix. If this does seem to be an issue i assume it should be more than okay for the new matrix to withstand for the rest of the life of the car if debris was to get into it. I’m not sure whether this is the original heater matrix i assume it is.

Thanks for your help V8.

 

[SuperV8]

Flushing the matrix out is only a temporary fix - I tried 5+ times hoping it would improve! In the end a new matrix was the fix.
The coolant tank usually says mit-silicate on it and contains a teabag sized bag of silicate. This can sometimes leak and cause a blockage - but also general detritus is enough to cause a blockage.
Again loads of posts on mit-silicate - if you have the 'teabag' consensus is to remove it - and change your coolant every 3-4 years.

I found my tank cap pressure relieve rather low so wise to test yours - and maybe get a new tank and cap.

 

[BillyCool]

I'd recommend changing the expansion tank as well as the matrix.

This is a guide I wrote that might help if you want to do a DIY matrix change.

 

[Luckyluck]

Hi all, I've already had a little look around to see if anyone has come into the same issue as me, but I cant seem to find someone with the exact same fault. It is either they heating all together isn't working or their vents are not working.

I've owned the car since Nov 23 and the fault has occurred since then the seller didn't advice me of this it was only brought to my attention when my father had used my car as his had stopped working.

Basically when the car gets to operating temperature the passenger side is nice and warm as it should be however, the driver side is just cold like the air con is on. (the center console vent driver side also doesn't seem to get to speed 6 but i think that is due to a different issue.)

This Leon is a single climate control spec.

I don't believe that the heater matrix is blocked or has died as heat does go to the passenger side. I've thought about flushing the heating system as I've read that a lot of the time there is a little bag in the coolant tank that splits and leave debris in the heater matrix, but I'm unsure on if that would do the trick as it seems to be an issue on delivery to the driver side of the car (I'm not smart when it comes to how car stuff works so all help is appreciated.)

My fathers cousin is a mechanic so he's messaged him today just waiting for a reply I just thought that in the meantime any advice on here would be greatly appreciated.

For context this is a right hand drive car, 1.6TDI engine that has clocked just under 170k miles.

Just flush out whole cooling system, replace the heater matrix and coolant expansion reservoir, then bleed the system.
Here you have a video with 2015 Leon.

It's well known issue for vag group. I've replaced mine about 2 weeks ago

 

[vixonss]

V8, Billy, Lucky, thank you for the all advice.

I’ve gone ahead and ordered both a new matrix and a new reservoir for my car hoping to have those arrive at the weekend so my dads cousin can get it sorted for me.

When you guys say bleed the system would i be correct on assuming you mean just empty out all the coolant from the cars system into a container? Would i need to put water through it after emptying the coolant before then adding the new coolant once the matrix and reservoir has been replaced.

Thank you.

 

[BillyCool]

Ideally, you want to dump as much of the old coolant (and associated crud) out of the engine as possible.

The EA288 engine has 3 coolant circuits. The one on the heater matrix actually has very coolant little in it, so you need to ideally drop the main radiator hose to ditch the majority of the coolant out.

The coolant circuits actually have some one way valves and can only be properly bled/flushed using VAG kit.

So, yes - dump as much coolant as you can. You could stick some tap water through (personally, I would use deionised water just to be careful) and see if it helps get any more crud out. Then top up with fresh coolant. Run the car, check when cold and top up again. The system is meant to self bleed any excess air out, so it may take a few drives and top ups to get it right.

 

[Luckyluck]

I wouldn't write it better BillyCool. I've removed the main radiator hose which is on the left bottom and I removed the the lowest one on the right as well.these are basically connected to top and bottom of the reservoir. Before I dumped all coolant I've bought coolant flush bottle and emptied it to system. I've used the car with it for a day, then following day I've dumped the coolant, flushed the system with runnig water from tap, to ensure as much debris removed from the system. Also when I've removed the heater matrix I've flushed both side pipes with running water, see picture ( please ignore removed dashboard, it was removed for a different reason} In home DIY condition if you don't have flushing machine I didn't figure out how to flush it with distilled water, tap water should be fine, just let it emptied completely as much as possible. About a week later I was replacing front panel and I've flushed whole system again, radiator I've flushed extra as I have it off the car. I've checked coolant reservoir for any debris after one week if anything was left is system but it was pretty clear. Then I topped it up with coolant when assembled back and bled the system with VCDS (it takes about 15mins to complete. There's plenty videos on YouTube. Let us know here if you need anything else

 

[Luckyluck]

I wouldn't write it better BillyCool. I've removed the main radiator hose which is on the left bottom and I removed the the lowest one on the right as well.these are basically connected to top and bottom of the reservoir. Before I dumped all coolant I've bought coolant flush bottle and emptied it to system. I've used the car with it for a day, then following day I've dumped the coolant, flushed the system with runnig water from tap, to ensure as much debris removed from the system. Also when I've removed the heater matrix I've flushed both side pipes with running water, see picture ( please ignore removed dashboard, it was removed for a different reason} In home DIY condition if you don't have flushing machine I didn't figure out how to flush it with distilled water, tap water should be fine, just let it emptied completely as much as possible. About a week later I was replacing front panel and I've flushed whole system again, radiator I've flushed extra as I have it off the car. I've checked coolant reservoir for any debris after one week if anything was left is system but it was pretty clear. Then I topped it up with coolant when assembled back and bled the system with VCDS (it takes about 15mins to complete. There's plenty videos on YouTube. Let us know here if you need anything else

Oh and I forgot.. don't forget to buy new fitting kit ( new clamps and seals for heater matrix)

 

[vixonss]

I'll get the coolant flushed, try remove as much as we can get out.

Both the heater matrix and coolant reservoir arrived today so hopefully i can leave an update with some actual heating when i manage to get it installed.

The matrix came with O rings, but no clamps. I assume the clamps already on the existing matrix will be fine as the matrix is the same measurements right?

 

[SuperV8]

Fine to re-use clamps - just make sure you use the correct allen/torx key.

 

[BillyCool]

I'll get the coolant flushed, try remove as much as we can get out.

Both the heater matrix and coolant reservoir arrived today so hopefully i can leave an update with some actual heating when i manage to get it installed.

The matrix came with O rings, but no clamps. I assume the clamps already on the existing matrix will be fine as the matrix is the same measurements right?

Just ensure that the bottom connection is properly snug and in place before tightening the clamp. If it's not quite located right, you'll get a small leak.

 

[vixonss]

Hi all

Just a little update so my cars booked in for Sunday and should have its heater matrix and coolant tank replaced Monday.

I've purchased a 4L bottle of Prestones Anti Freeze Coolant, I was wondering if 4L would be enough for the whole system?

Never flushed coolant before only had my father top it up so I just want to get ahead of it if I do need to purchase another bottle of coolant before Sunday.

Thanks in advance you've all be wonderfully helpful.

 

[Walone]

Hi all

Just a little update so my cars booked in for Sunday and should have its heater matrix and coolant tank replaced Monday.

I've purchased a 4L bottle of Prestones Anti Freeze Coolant, I was wondering if 4L would be enough for the whole system?

Never flushed coolant before only had my father top it up so I just want to get ahead of it if I do need to purchase another bottle of coolant before Sunday.

Thanks in advance you've all be wonderfully helpful.

Is Prestones Anti Freeze Coolant VW/VAG/Seat approved? Think it needs to be G12 or G13?

 

[tracktoy]

Do you have a scanning tool that allows you to do basic settings.

If so have you tried running Adapt flap end stops as sometimes it can help (but I would agree its normally heater matrix)

 

[SuperV8]

Hi all

Just a little update so my cars booked in for Sunday and should have its heater matrix and coolant tank replaced Monday.

I've purchased a 4L bottle of Prestones Anti Freeze Coolant, I was wondering if 4L would be enough for the whole system?

Never flushed coolant before only had my father top it up so I just want to get ahead of it if I do need to purchase another bottle of coolant before Sunday.

Thanks in advance you've all be wonderfully helpful.

Cooling system capacity is 8L

 

[vixonss]

Update to all.

Thank you all so much with the fast responses, especially V8.

Turns out it was indeed the heater matrix that was blocked once the system was bled reservoir replaced and matrix replaced there's some nice heat being produced now. (Parts and labour was £110 i was expecting a heftier bill)

I appreciate everyone who helped with information etc, hopefully people with the same issue stumble upon this thread.

Thank you so much everyone!

 

[vixonss]

Apologies on reviving a dead thread.

So its been 7 months, and unfortunately I am back to square one. Cold air drivers side warm air passengers side.

Now I would like to fix this as I do quite like the car, if anyone has any ideas on what could be wrong.

When the matrix was replaced with a new one hot air all round. I've been back to cold air for maybe 2 months now which hasn't bothered me all be it with summer, but with the colder mornings arriving my entire car takes forever to demist.

I'm in no way a mechanic, but surely this is down to a delivery path from the hot air as it makes it to the left side fine but the drivers side is a bit of a hassle.

For a little bit of context if i have my heater on max facing the windscreen, then i change it to blow on occupants I will get maybe 5 seconds of hot air through the drivers side then its back to cold air.

If anyone has any ideas I am all for hearing them. Not sure whether to take it to Seat directly and see what they quote me for the 'cause of the issue'

Thanks for reading!

 

[MartinThorn]

Update to all.

Thank you all so much with the fast responses, especially V8.

Turns out it was indeed the heater matrix that was blocked once the system was bled reservoir replaced and matrix replaced there's some nice heat being produced now. (Parts and labour was £110 i was expecting a heftier bill)

I appreciate everyone who helped with information etc, hopefully people with the same issue stumble upon this thread.

Thank you so much everyone!

£110 sounds far too cheap to me for replacing a heater matrix (I was quoted over £1000! from an independent). Are you *sure* they replaced the matrix rather than just flushing the system!?