HELP ME PLEASE!!!

[SuperV8]

Guys, for future reference, I've just changed the heater matrix on a Mk3 leon 2.0 tdi Fr.. Fairly straightforward to be fair. Now the car has toasty heating again I thought I'd have a play with the old (blocked matrix) 1) Dissolved a dishwasher tablet in boiling water and filled matrix (has to fill inlet and outlet sides) capacity is minimal. Left to Soak for a couple of hours... note :the face of the matrix wasn't even getting warm 2)Drained and flushed through with garden hose for 5 mins ( after which time water was passing through the matrix. 3) Did a 2nd fill with boiling dishwasher water and soaked for half hour... note: face of the matrix was now quite warm and only had to fill one side to completely fill it. 4) Again flushed with garden hose and water running freely through the matrix 5) To make sure blew through with compressed air (I have a compressor) but probably not needed. I'm now convinced my old matrix is completely clear and wished I hadn't rushed out and spent £165 on a new matrix. So if you have the time then following this procedure before buying a new matrix could save you a Bob or two.

This is only a temporary fix.
I cleaned and flushed mine (using various cleaning solutions - including the dishwasher tablet dissolved in boiling water) 5 or 6 times! Each time it would work fine for a few months - then bam - coolant low warning light.
I was hoping that the time between each of these 'cleans' would get longer and longer to the point I wouldn't have to do it again! but after 5 or 6 I thought sod it and brought a new matrix (June 2021), and glad I did, has been perfect since; 15 months+.
I noticed heater matrix's are very seasonally priced - being £100+ in Autumn & Winter - and mine only cost £35 in the summer!

 

[Mk3 1.4tsi CHPA]

I replaced mine in March following the above video in about 3 hours and that included taking my time.

I've sent instructions to about 3 others members on the same subject so drop me a DM if you need any help with sourcing your matrix, tools, fitting, photos etc.

The matrix is never usually fully blocked but has restricted water flow due to the combination of possible silicant gel from the split bag in the header tank and casting sand from the engine block. You can try to flush it out (I tried 3 times) but compared to a new one, it's never as good.

Hello mate, I was hoping if you had any advises or instructions for this please, are there any specific tools needed ? Any help is much appreciated, Thanks.

 

[BillyCool]

Hello mate, I was hoping if you had any advises or instructions for this please, are there any specific tools needed ? Any help is much appreciated, Thanks.

Hiya,

The You Tube video is very helpful and also some comments from personal experience:

Extra tips:

Line the footwell with thick plastic sheeting and then have some towels and kitchen towel ready. You WILL spill some, although only about 300ml actually comes out of the matrix (it's the smallest of the 3 coolant circuits).

There are 3 screws holding the blower motor in place. The one at the back is hard to get to, so a short T25 (or whatever size it is) on a small ratchet works best. Anything longer is hard to fit in the footwell.

When you remove the glovebox/multimedia unit - label all of the wires and remember (write down) what order things came out. There is a footwell light and glovebox light and it's easy to forget what goes where.

When you re-attach the pipes to the matrix - on the lower pipe make sure that the pipe is fully in and the retaining collar on the back is fully engaged and clips on to the back properly, otherwise it will leak a little (there is a small lip and it need to sit over that).

Also be careful when sliding in the new matrix. They are very easy to damage. Just be patient and take your time. Don't force it if it doesn't feel right.

The coolant circuit on the car is quite complex and you need special tools to fully flush/bleed it. As I was having my water pump changed (another known issue), I just got my mechanic to drop the main rad hose so most of my coolant got changed anyway. I never got it properly (professionally) flushed but it's been fine for nearly 3 years.

I bought my matrix from Europe due to lack on UK stock. Cost me about €90.

The Valeo was what was already in my car:

https://www.buycarparts.co.uk/search?keyword=715303&maker_id=104&model_id=11484&car_id=23695&kbaStr%5B0%5D=YE14WMM

It took me a couple of hours to do and I faffed a bit.

I did take some pictures as well so let me know if you need anything.

Good luck with it.

 

[iainbert]

Hello,
Been reading these threads for a few weeks now.
My car is currently in the garage just now getting this "seen to" after having my timing belt already changed last year by them.
The mechanic has stressed to me how it takes ages and I need a new expanding aswell when doing this

Can someone confirm if that's the case or do I just need a new matric and a flush the system?

 

[BillyCool]

Hello,
Been reading these threads for a few weeks now.
My car is currently in the garage just now getting this "seen to" after having my timing belt already changed last year by them.
The mechanic has stressed to me how it takes ages and I need a new expanding aswell when doing this

Can someone confirm if that's the case or do I just need a new matric and a flush the system?

I think I understand your question.

Is your mechanic saying that you need to replace the expansion tank as well? I would agree with that, just to be safe. The tank needs to be one without the silicate bag in it.

If he has stressed "it takes ages", do you mean to replace the matrix? It can be done in under 2 hours quite easily (watch the video). SEAT say it takes 8 hours as their service guide is to take the whole dashboard out. The DIY fix is far simpler.

 

[iainbert]

I think I understand your question.

Is your mechanic saying that you need to replace the expansion tank as well? I would agree with that, just to be safe. The tank needs to be one without the silicate bag in it.

If he has stressed "it takes ages", do you mean to replace the matrix? It can be done in under 2 hours quite easily (watch the video). SEAT say it takes 8 hours as their service guide is to take the whole dashboard out. The DIY fix is far simpler.

Yeah sorry, me being me and typical didn't re read what I posted.
Expansion tank yes.

So I just got the car back, the mech said how the car was "running and the system under pressure" but nothing. So he hasn't touched it.

But when I've got in the cooling is at low etc I explained to him twice that its only when I put the temperature up it blows the coolant out.
Also the A/C isn't cold, it's cool but not cold like it was when he regassed it last year.

So at this stage I'll be watching that video and looking at doing it myself at some point

 

[Compo1]

Hi lads

Got this problem so ill give it a go myself.

Is there a specific aftermarket matrix people have been using . Ive read something along the line is on make has larger coolant channels ?

 

[BillyCool]

Hi lads

Got this problem so ill give it a go myself.

Is there a specific aftermarket matrix people have been using . Ive read something along the line is on make has larger coolant channels ?

The OEM one is usually Valeo.

The one with the wider channels is a NISSENS one:

https://www.autodoc.co.uk/nissens/7589648

I fitted a Valeo and have had no issues for 4+ years. I've heard some people have fitted the NISSENS one.

Please check to ensure that it is the correct one for your car.

 

[Compo1]

The OEM one is usually Valeo.

The one with the wider channels is a NISSENS one:

https://www.autodoc.co.uk/nissens/7589648

I fitted a Valeo and have had no issues for 4+ years. I've heard some people have fitted the NISSENS one.

Please check to ensure that it is the correct one for your car.

Thanks for that bud.

Did you need to removed the blower motor ? If you did was that difficult ?

 

[BillyCool]

Thanks for that bud.

Did you need to removed the blower motor ? If you did was that difficult ?

I did remove the blower and it's not that bad. Getting the glovebox and media unit out was more of a faff.

I've actually written some instructions, so see if that helps. The You Tube video helped me massively.

 

[Compo1]

I did remove the blower and it's not that bad. Getting the glovebox and media unit out was more of a faff.

I've actually written some instructions, so see if that helps. The You Tube video helped me massively.

Thank you

Really appreciate those instructions.

 

[Compo1]

Sorry to be a pain what antifreeze do i require with a header tank silicate free ?

I thought you needed an antifreeze with silicates when you remove the bag and see G12 Evo mentioned as suitable.

But i understand g12 evo is silicate free.

Doing the matrix this weakened or next so need to get some.

 

[cuthound]

Sorry to be a pain what antifreeze do i require with a header tank silicate free ?

I thought you needed an antifreeze with silicates when you remove the bag and see G12 Evo mentioned as suitable.

But i understand g12 evo is silicate free.

Doing the matrix this weakened or next so need to get some.

G12 Evo.

Genuine VW SEAT Audi Skoda G12 Evo Pre-Mixed Coolant 1 Litre

Shop Genuine VW SEAT Audi Skoda G12 Evo Pre-Mixed Coolant 1L online at SEAT Motor Parts. We have a range of products available for your SEAT.

www.coxmotorparts.co.uk

 

[RUM4MO]

When I changed the coolant in my car, I had no option other to buy G12evo 50-50 pre mixed in 1ltr bottles, but now, it might be possible to buy it in larger containers like 5ltr - if I'm correct there, that should mean that you'll get charged a lot less per litre.

 

[Compo1]

Well heater Matrix swapped today. I'd flushed the cars coolant system out twice during the week with DI water as i only got around 4 litres out the first time i drained it despite removing every coolant pipe i could, so topped up bled system and drained again.

Swapping the matrix and using VCDS to bleed the system 2 1/2 hrs thanks to @BillyCool instructions

I used a Nissens matrix for autodoc £75 could of used a £40 NRF one but went with the Nissens as it seems well recommended.

 

[iainbert]

Guess what I haven't bothered with because it was summer? Yup. Now the weather has dropped here in Scotland I need to address this.
Fingers crossed I'll be doing it in the next 2 weeks, but does anyone have a part number or an expansion tank they used to replace the old one?

 

[MartinThorn]

When I changed the coolant in my car, I had no option other to buy G12evo 50-50 pre mixed in 1ltr bottles, but now, it might be possible to buy it in larger containers like 5ltr - if I'm correct there, that should mean that you'll get charged a lot less per litre.

I bought this bigger 5L container from eurocarparts (yes, cheaper than 5-off 1L bottles): https://www.eurocarparts.com/search/523772601

I also bought 2 off 1L containers in addition because I read somewhere that the car's coolant capacity was 7-8L (I disconnected the lower hose). In the end I only had to put about 4L back in after replacing the Matrix so I suspect not everything came out..

 

[RUM4MO]

@iainbert, yes getting a bit cold now, I "buttoned up" all outstanding jobs on my car for now, so that we can get my wife's car back into the garage!

I've asked another poster on another Leon thread to share the p/n of the new reservoir, so maybe the info you asked for will appear there.

 

[BillyCool]

Guess what I haven't bothered with because it was summer? Yup. Now the weather has dropped here in Scotland I need to address this.
Fingers crossed I'll be doing it in the next 2 weeks, but does anyone have a part number or an expansion tank they used to replace the old one?

Just the expansion tank or the matrix as well?

 

[iainbert]

Just the expansion tank or the matrix as well?

Be aswell doing both


**edit** sorry the part number for the expansion tank