Coolant blown out from expansion bottle

Janchee

Member
Joined
Sep 12, 2021
Location
UK
TDI
VW Golf MK7 1.6 TDI 105 Manual 2014
1 year later … and my 1.6 CLHA mk7 golf manual blocked again (even with new matrix) and I think I know why.

I only drained the front main radiator and intercooler radiator last year when changing the matrix. I was also happily squeezing all the hoses afterward to get rid of air … which might of accelerated stuck sludge straight into the new matrix! You live and learn.

Anyway, spent the Saturday morning fixing it. This time also removed pipe from rear electric pump when draining coolant and loads more coolant came out. Bought the heater matrix (linked somewhere on this forum) which has bigger ‘holes’ etc. about £110 incl delivery. Idea of bigger holes sounded good as I don’t think I’ll ever flush it properly on my drive or pay VW thousands to do it!

Well, in the end I had to properly flush and refit the oem part I installed a year ago! This other new matrix I had bought was a pain! It was hard to slide into the matrix hole and then I couldn’t for the life of me get the pipes on past the o-rings! Seems like the oem one has a chamfer to slowly squeeze the o ring into it and this one is just 90deg edge. I gave up in the end as it would be my luck that the o ring would be damaged on reassembly!

Tried doing the bleeding via OBDeleven and just couldn’t get any of it to work. VCDS definitely seems like a good option for this.

I did vacuum fill and the golf only took 4.7 l of G12Evo. I see sites quoting 8l capacity so I must of missed some coolant somewhere!

Heating now back in the drivers side ready for the colder days in UK.

Some top tips
- Get a pair of long wire hose clamp pliers! It’s tight when you need to remove pipes from pumps (as they’re not quick release clips)
- If possible, get vcds or find a friend that does have it!
- Replace coolant reservoir. I did mine last year as it had so much bad stuff in it !
- use OEM or similar part. If you’re doing it on your driveway, last thing you want is to be effing and jeffing with a matrix that doesn’t fit or is awkward!
- I bought a cheap vacuum kit on eBay for £30 last year and it works really well.
 

Janchee

Member
Joined
Sep 12, 2021
Location
UK
TDI
VW Golf MK7 1.6 TDI 105 Manual 2014
Hi there,

I've just been pointed to this thread. I've got a 2 litre diesel Skoda Octavia. I've got coolant levels dropping slowly (and looking a little murky - but I don't believe it's a head gasket issue) and also have no hot air (going to confirm later if it's just some fans blowing cold). Garage is unsure what it could be and is suggesting replacing parts methodically (fortunately they don't want to waste my money like a main dealer).

There's a lot of info in here, much of which I don't understand. I was wondering if anyone could advise on any sort of specific checks that can be done to try and confirm if my issue is the heater matrix?

I've read about an issue being regeneration related. Unfortunately I don't actually know how I can tell if my car is doing a regen or not: ( Also I've seen people mention a coolant overflow (is that an overflow valve, or when removing the cap when the engines hot)? Hoping someone could point this car n00bie in the right direction!

Thanks
Get it sorted? Will be matrix. Look for pink / white spots on engine mount. DPF regen causes very hot coolant to be injected into matrix and if it’s blocked, it’ll go via the air bleed pipe at high pressure to the reservoir and will be released via the cap. The coolant reservoir cap has an automatic bleed off pressure hence why your levels will drop and you may see pink spots on the engine mount! Another tell tale sign of matrix is a basic coolant leak test will come back ok because there technically isn’t one :)
 

ipwright83

New member
Joined
Jul 18, 2023
Location
UK
TDI
Skoda Octavia
Thanks for the advice on here. I've just got my Octavia back today with hopefully the coolant leak fixed.

My heater matrix was totally gummed up. The silica bag removed from the replacement. It took a while to get sorted as I also had an accuator fault on a heating vent meaning half the car wouldn't have heated anyway.
 

scaper28

Member
Joined
Mar 21, 2024
Location
UK Gloucester
TDI
Golf 2.0 GT TDI 2013
After reading this post I think I have the same issue ,

I have just had a quick look to see which version of the heater matrix I have the A or B however I have not had chance to remove the glove box yet. can anyone tell by my pictures by any chance ?


also what is the best way to do a flush of the system ,

" Picture share link below "

2 Items
 

FJBGTD

Member
Joined
Jun 13, 2022
Location
Southampton
TDI
Golf GTD
After reading this post I think I have the same issue ,

I have just had a quick look to see which version of the heater matrix I have the A or B however I have not had chance to remove the glove box yet. can anyone tell by my pictures by any chance ?


also what is the best way to do a flush of the system ,

" Picture share link below "

2 Items
It is a Valeo, you can see it printed on the plastic matrix cover in your picture.
 

scaper28

Member
Joined
Mar 21, 2024
Location
UK Gloucester
TDI
Golf 2.0 GT TDI 2013
It is a Valeo, you can see it printed on the plastic matrix cover in your picture.
Thank you very much is that the A or the B version ?


When I went to VW parts they said its either the 5Q0 819 031 A or the 5Q0 819 031 B

Due to them wanting £300 odd for the part I want to make sure I get the correct one.
 

FJBGTD

Member
Joined
Jun 13, 2022
Location
Southampton
TDI
Golf GTD
Thank you very much is that the A or the B version ?


When I went to VW parts they said its either the 5Q0 819 031 A or the 5Q0 819 031 B

Due to them wanting £300 odd for the part I want to make sure I get the correct one.
Valeo is 5Q0819031B, £300 is a ridiculous price, get a quality aftermarket unit like Nissens or NRF for less than £100.
 
Joined
Feb 23, 2023
Location
Scotland
TDI
20 ltr
I have the same issue 20 tdi loosing water out the coolant bottle…spent fortunes on it replaced everything imaginable, mechanic has told me it’s now finally sorted I’ve to collect car tonight after he road testers it today. Still not sure what was the cause I’ll find out later
 

scaper28

Member
Joined
Mar 21, 2024
Location
UK Gloucester
TDI
Golf 2.0 GT TDI 2013
Valeo is 5Q0819031B, £300 is a ridiculous price, get a quality aftermarket unit like Nissens or NRF for less than £100.


I thought it was expensive , you don't have any links to where I can get a good aftermarket one by any chance as I want to make sure I get the correct one .

Thanks for your help I appreciate it
 

scaper28

Member
Joined
Mar 21, 2024
Location
UK Gloucester
TDI
Golf 2.0 GT TDI 2013
Try Parts in Motion https://www.partsinmotion.co.uk/ put 5Q0819031B in the search box.

They only sell quality parts.

Thank you , I will have a look on there now. WOW so so much cheaper , I am torn between either the NRF one at £72 or the FEBI one at £91 ?

One last thing , I was going to dump all the water out of the car by removing the radiator pipe. is there a better way to flush the system though or do I not need to ?
 
Last edited:

FJBGTD

Member
Joined
Jun 13, 2022
Location
Southampton
TDI
Golf GTD
Thank you , I will have a look on there now.

One last thing , I was going to dump all the water out of the car by removing the radiator pipe. is there a better way to flush the system though or do I not need to ?
Try and get as much water out as possible and flush through with clean water. To fill the system properly, you will need a scan tool to activate the bleed process and a vacuum fill device. You can do it manually but you will likely hear the sound of water running behind the dash for a while until all the air works its way out.
 

scaper28

Member
Joined
Mar 21, 2024
Location
UK Gloucester
TDI
Golf 2.0 GT TDI 2013
Try and get as much water out as possible and flush through with clean water. To fill the system properly, you will need a scan tool to activate the bleed process and a vacuum fill device. You can do it manually but you will likely hear the sound of water running behind the dash for a while until all the air works its way out.
Right so if I am right in thinking , remove radiator pipe. unscrew expansion tank cap once all water out , run a hose into the expansion tap and leave running until nice and clear. then change the heater matrix, fill with G12EVO and run VCDS bleed cycle

I am so glad I posted on here thank you so much for your help.
 

FJBGTD

Member
Joined
Jun 13, 2022
Location
Southampton
TDI
Golf GTD
Right so if I am right in thinking , remove radiator pipe. unscrew expansion tank cap once all water out , run a hose into the expansion tap and leave running until nice and clear. then change the heater matrix, fill with G12EVO and run VCDS bleed cycle

I am so glad I posted on here thank you so much for your help.
That is pretty much all you can do without a VW flushing machine. You could put the rad hose back on and remover other cooling pipes, such as the charge cooler and heater pipes on the bulk head, and run the hose again.
 

scaper28

Member
Joined
Mar 21, 2024
Location
UK Gloucester
TDI
Golf 2.0 GT TDI 2013
That is pretty much all you can do without a VW flushing machine. You could put the rad hose back on and remover other cooling pipes, such as the charge cooler and heater pipes on the bulk head, and run the hose again.
Thanks I will try those for a good flush of the system.


Just trying to work out which part to get the £71 NRF or the £91 FEBI one ::ROFLMAO:
 

Janchee

Member
Joined
Sep 12, 2021
Location
UK
TDI
VW Golf MK7 1.6 TDI 105 Manual 2014
Thanks I will try those for a good flush of the system.


Just trying to work out which part to get the £71 NRF or the £91 FEBI one ::ROFLMAO:
Try and disconnect both pumps at front and back of engine block. Note that some aftermarket parts don’t slide in like VW ones so make sure you’re ready to have patience.

I replaced my coolant reservoir tank whilst I was at it as that was full of gunk.

If you flush with hose, make sure you get all of that out as it will react with internal components.
 

scaper28

Member
Joined
Mar 21, 2024
Location
UK Gloucester
TDI
Golf 2.0 GT TDI 2013
Try and disconnect both pumps at front and back of engine block. Note that some aftermarket parts don’t slide in like VW ones so make sure you’re ready to have patience.

I replaced my coolant reservoir tank whilst I was at it as that was full of gunk.

If you flush with hose, make sure you get all of that out as it will react with internal components.
Ah that is a concern as I dont want to be stuck trying to get it in and the pipes to seal/fit correctly. Which part one did you use I am still debating over the NRF or Febi or now even another make lol

I have purchased a new reservoir tank and cap also and 10Litres of G12Evo .


is there a better fluid to flush with , distilled water or something ?
 

Janchee

Member
Joined
Sep 12, 2021
Location
UK
TDI
VW Golf MK7 1.6 TDI 105 Manual 2014
Ah that is a concern as I dont want to be stuck trying to get it in and the pipes to seal/fit correctly. Which part one did you use I am still debating over the NRF or Febi or now even another make lol

I have purchased a new reservoir tank and cap also and 10Litres of G12Evo .


is there a better fluid to flush with , distilled water or something ?
Make sure you have some long reach flexible hose pliers. They are a god send :)

I tried the heater matrix which claims they use bigger holes (around £100). I couldn’t for the life of me get the part into the ducting. I sent it back and in fairness to the company, they provided a full refund.

I then managed to find a brand new genuine Heater matrix on eBay which had never been used for £70.

Distilled water would be better as you’re then not concerned about it. It’s not a deal breaker though.
 

scaper28

Member
Joined
Mar 21, 2024
Location
UK Gloucester
TDI
Golf 2.0 GT TDI 2013
Make sure you have some long reach flexible hose pliers. They are a god send :)

I tried the heater matrix which claims they use bigger holes (around £100). I couldn’t for the life of me get the part into the ducting. I sent it back and in fairness to the company, they provided a full refund.

I then managed to find a brand new genuine Heater matrix on eBay which had never been used for £70.

Distilled water would be better as you’re then not concerned about it. It’s not a deal breaker though.

Wow £70 for a new genuine one that was a lucky find...

Did you use distilled water on yours then and the long reach flexible hose pliers for the engine wall pipes ?
 
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