Coolant blown out from expansion bottle

Kamei1507

New member
Joined
Aug 29, 2019
Location
Holland
TDI
Seat Leon st 1.6tdi 12/2014
Had mine done 3 weeks
Ago no coolant loss. but still have engine temp at 120 degrees when driving 140km/h.went for a drive in Germany 200km/h max oil temp 136 before matrix troubles 115. Makes me wonder. Asked friendly and they said no problem. Coolant temp stays between 88/96
 

SkilledMilk

Member
Joined
Mar 31, 2018
Location
Glasgow
TDI
Leon MK3 (184) 2013
To reply to Theo95, you've mentioned something that I neglected to mention in my previous posts regarding my experiences. Because I had the issue for so long, I also noticed that if a regen was carried out when the car was stationary then no overflow occurred.
As DrSchultze suggested, all your symptoms seems to match those of other members so I'd start by changing the heater matrix. Attached are some photos of my own when I swapped them out. Part number 5Q0.819.031.


 
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Spipa

Active member
Joined
Jul 18, 2019
Location
Netherlands
TDI
Mk 7 GTD
Just ordered the heater matrix for €90. Decided that I will try to do it myself this weekend. Does anyone have a (youtube) video which shows how to replace the part?
 

alscrxangels

New member
Joined
Sep 9, 2019
Location
Ireland
TDI
Leon
Same thing happening to my 2014 Seat Leon FR 184. It's very frustrating.

I had my friend, who is a mechanic look at it and he went the same route as a lot of the members here and diagnosed it as a blocked heater matrix but could have been a faulty water pump. We replaced the water pump and flushed the system a few times. The heating came back but the persistent problem of the coolant fluid being pushed out the tank still continued.

I read up and narrowed it down to it happening when the DPF regen kicked in. It was interesting to read the different types of regen that can happen but what I found interesting on one of the sites I read was that the regen kicked in within 50km (or something like that) after you filled your car with Diesel. Seems to be happen everytime for me. So I've monitored when the engine revs get uplifted by the ecu and sure enough I lose coolant.

Reading this thread has been fantastic and so I believe I am left with 2 options to resolve it.
1 - In Ireland (so I read) we can legally remove the DPF, the sensor and stop it on the ECU (there is a place in Dublin that specializes in it). Cost €550. Result, the DPF does not kick in and the load does not come onto the heating matrix.
2 - Replace the heater matrix to the improved one you guys are suggested in the car myself and flush the system to make sure everything is clean. Cost €100 plus my time.

Needless to say I am following the advice previously in this thread and going with replacing the heating matrix. I see a Nissen one and a Valeo one - I assume both work fine so I am going to order one up and give it a go.


On another note I have to agree that it is worrying that the VAG range of manufacturers do not know what needs to be gone and how to diagnose this properly. I purposely did not go to a main dealer to get it looked at because I think that they either a) know the problem but know they can charge you for further work; b) it's a known issue/defect and they do not want to admit it and get recalls or c) they simply do not have the experience to diagnose things properly ...... I am talking about this from past experiences.....but enough of my conspiracy theories :)

I'm just delighted that groups of people on these forums can come together to troubleshoot these things to a point where we have confidence in the solution.

Keep the post coming and I'll let you know how mine goes once I get it.
 

SkilledMilk

Member
Joined
Mar 31, 2018
Location
Glasgow
TDI
Leon MK3 (184) 2013
Same thing happening to my 2014 Seat Leon FR 184. It's very frustrating.

I had my friend, who is a mechanic look at it and he went the same route as a lot of the members here and diagnosed it as a blocked heater matrix but could have been a faulty water pump. We replaced the water pump and flushed the system a few times. The heating came back but the persistent problem of the coolant fluid being pushed out the tank still continued.

I read up and narrowed it down to it happening when the DPF regen kicked in. It was interesting to read the different types of regen that can happen but what I found interesting on one of the sites I read was that the regen kicked in within 50km (or something like that) after you filled your car with Diesel. Seems to be happen everytime for me. So I've monitored when the engine revs get uplifted by the ecu and sure enough I lose coolant.

Reading this thread has been fantastic and so I believe I am left with 2 options to resolve it.
1 - In Ireland (so I read) we can legally remove the DPF, the sensor and stop it on the ECU (there is a place in Dublin that specializes in it). Cost €550. Result, the DPF does not kick in and the load does not come onto the heating matrix.
2 - Replace the heater matrix to the improved one you guys are suggested in the car myself and flush the system to make sure everything is clean. Cost €100 plus my time.

Needless to say I am following the advice previously in this thread and going with replacing the heating matrix. I see a Nissen one and a Valeo one - I assume both work fine so I am going to order one up and give it a go.


On another note I have to agree that it is worrying that the VAG range of manufacturers do not know what needs to be gone and how to diagnose this properly. I purposely did not go to a main dealer to get it looked at because I think that they either a) know the problem but know they can charge you for further work; b) it's a known issue/defect and they do not want to admit it and get recalls or c) they simply do not have the experience to diagnose things properly ...... I am talking about this from past experiences.....but enough of my conspiracy theories :)

I'm just delighted that groups of people on these forums can come together to troubleshoot these things to a point where we have confidence in the solution.

Keep the post coming and I'll let you know how mine goes once I get it.
A fellow right hand drive Leon owner!

From the sounds of it I think the matrix change should fix your problem, in any case will result in a much hotter heater for when the weather is bad (most of the time). I'd almost try to sway you away from the Valeo part as thats what the original matrix in my car was (see previous post with photos). As mentioned it was difficult to blow air through it once removed, indicating that the channels had become restricted or blocked somehow. The Nissens one has noticeably larger channels which may help prevent them being clogged up with any remnant debris and the problem recurring few months down the line. This also might explain why those that have had the matrix replaced at the dealer saw the issue come back as the dealer would use the original equipment part.

In any case let us know how you get on. I agree with you regarding the main dealers, I was keen to steer clear as so many had expensive work done with nothing to show for it.
 

Theo95

New member
Joined
Sep 9, 2019
Location
Romania
TDI
Golf 7 2.0 TDI
Thank you all for your replies.
Have you all bought the Nissen one? Also, have you all flashed the old coolant? Mine looks pretty clean. In 6k kms I think I changed it two times little by little. Not to mention my previews owner. I remember he said he had the heating problem when he changed the water pump and timing belt at the VW Dealership, but the problem got solved there. I talked to the guys at that dealership and they didn't mention this problem we all have with blowing coolant, they said the car is in perfect condition. So I suspect the car did at least 20k kms with this problem, I hope it didn't affect anything else.

@DrSchultze, @SkilledMilk Do you know if 73980 is the product code for the Nissen heater matrix you bought? I see that there are two Nissen heaters, the other one is 73943, but I think the first one is the right one.

@alscrxangels My opinion is that removing the DPF is not a good idea, maybe just as a last resort. The drivers that are going to drive behind you will not be so happy about this, they're going to feel an acid smell from the gases. Is it legal in your country, but is the car going to pass the periodical inspection in terms of emissions? And yea... it's pretty sad that the VAG is not recognizing this as a common issue. Maybe they don't communicate with each other and don't report the issue.
 
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BirdmanofTas

Member
Joined
Aug 13, 2019
Location
Australia
TDI
2013 Golf Mk7 Highline TDI
Thank you all for your replies.
Have you all bought the Nissen one? Also, have you all flashed the old coolant? Mine looks pretty clean. In 6k kms I think I changed it two times little by little. Not to mention my previews owner. I remember he said he had the heating problem when he changed the water pump and timing belt at the VW Dealership, but the problem got solved there. I talked to the guys at that dealership and they didn't mention this problem we all have with blowing coolant, they said the car is in perfect condition. So I suspect the car did at least 20k kms with this problem, I hope it didn't affect anything else.

@DrSchultze, @SkilledMilk Do you know if 73980 is the product code for the Nissen heater matrix you bought? I see that there are two Nissen heaters, the other one is 73943, but I think the first one is the right one.

@alscrxangels My opinion is that removing the DPF is not a good idea, maybe just as a last resort. The drivers that are going to drive behind you will not be so happy about this, they're going to feel an acid smell from the gases. Is it legal in your country, but is the car going to pass the periodical inspection in terms of emissions? And yea... it's pretty sad that the VAG is not recognizing this as a common issue. Maybe they don't communicate with each other and don't report the issue.

The Nissens one i got was the 73980, VAG Number 5Q0819031B.. B being the latest version..
 

mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
I just noticed that my VW Dealer fitted the A version of the Heatermatrix (5Q0819031A) Is this a bad version, any evidence for this ???
 

Theo95

New member
Joined
Sep 9, 2019
Location
Romania
TDI
Golf 7 2.0 TDI
I see that 5Q0819031A is the "Denso version" of the heater matrix and 5Q0819031, 5Q0819031B are the "Valeo versions".

Maybe the Denso one is not compatible with the Valeo one and just the Valeo one has a revised version. We should ask a dealership what are the differences between these 3.

But you said your problem is gone, right?
 
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mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
I see that 5Q0819031A is the "Denso version" of the heater matrix and 5Q0819031, 5Q0819031B are the "Valeo versions".

Maybe the Denso one is not compatible with the Valeo one and just the Valeo one has a revised version. We should ask a dealership what are the differences between these 3.

But you said your problem is gone, right?

Yes !!! Problem is gone, my fear is that i will end up having the same problems again after 90.000km. I just would like to be sure that the 5Q0819031A Denso is not a recall-product....
 

BirdmanofTas

Member
Joined
Aug 13, 2019
Location
Australia
TDI
2013 Golf Mk7 Highline TDI
Yes !!! Problem is gone, my fear is that i will end up having the same problems again after 90.000km. I just would like to be sure that the 5Q0819031A Denso is not a recall-product....
the version A and the verison B matrix's look almost identical, the original one i cut in pieces to have a look was slightly smaller than both of them in the cores, but it was only slightly (.25 mm).. i know the version B was released after july this year, but i cant see much of a difference to the A version.. as the overall volume of the matrix's has not increased enough to matter, its all about the flow.. so as long as your coolant system stays clean it should be fine.. i plan to disconnect the hoses at the firewall every so often, and back flush the matrix to minimise any sediment being able to settle, buildup and clog the cores in future.. its about a 10 minute job to disconnect the fittings, back flush and re assemble, and you can do it without removing anything from the engine bay.
 

mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
the version A and the verison B matrix's look almost identical, the original one i cut in pieces to have a look was slightly smaller than both of them in the cores, but it was only slightly (.25 mm).. i know the version B was released after july this year, but i cant see much of a difference to the A version.. as the overall volume of the matrix's has not increased enough to matter, its all about the flow.. so as long as your coolant system stays clean it should be fine.. i plan to disconnect the hoses at the firewall every so often, and back flush the matrix to minimise any sediment being able to settle, buildup and clog the cores in future.. its about a 10 minute job to disconnect the fittings, back flush and re assemble, and you can do it without removing anything from the engine bay.

@BirdmanofTas Thank you for explaining the difference ! Today i visited an independent garage and they claimed they know about this specific problem (heater matrix blocked(. They advice their customers to flush the heater core every 30.000 km or use an add on to the coolant which keeps the coolant clean.
 

mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
The coolant blow outs have been gone for about 3000 km, i am confident that replacing the heater matrix sovled this problem. I noticed the car is still loosing/using coolant. Either the EGR of the head ????? I noticed that the coolantsystem is pressurized even after the car cooled down, i always thought it was a closed system and only the heat of the coolant pressurizes the system, does anybody understands this ??? How are you doing in solving the problem ???
 

Spipa

Active member
Joined
Jul 18, 2019
Location
Netherlands
TDI
Mk 7 GTD
The coolant blow outs have been gone for about 3000 km, i am confident that replacing the heater matrix sovled this problem. I noticed the car is still loosing/using coolant. Either the EGR of the head ????? I noticed that the coolantsystem is pressurized even after the car cooled down, i always thought it was a closed system and only the heat of the coolant pressurizes the system, does anybody understands this ??? How are you doing in solving the problem ???
I just replaced the heater core also, the heating works now perfect again. Only time will tell if the blow outs won’t happen again to my car.

How severe is your coolant loss after replacing the heater core?
 

mm-rocco

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Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
I just replaced the heater core also, the heating works now perfect again. Only time will tell if the blow outs won’t happen again to my car.

How severe is your coolant loss after replacing the heater core?

@Spipa Good to hear that you replaced the heater core ! The coolant loss is about 1 liter per 1000km, that is a rough calculation. The blown outs are gone so i suspect that i had two (or more :) ) faulty parts.
 

Spipa

Active member
Joined
Jul 18, 2019
Location
Netherlands
TDI
Mk 7 GTD
@Spipa Good to hear that you replaced the heater core ! The coolant loss is about 1 liter per 1000km, that is a rough calculation. The blown outs are gone so i suspect that i had two (or more :) ) faulty parts.
Oh that is a lot. How much did you lose before replacing the heater core? Because I had to refill with only 300/400ml after every blow out (about 1000km). I have to say that before my head gasket was replaced, I had to refill with about 1 liter every blow out, so maybe it is indeed a combination of both.
 

mm-rocco

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Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
I have a DPF every 300-350 km, the loss of coolant this time is not related to DPF. It looks like the care is using the coolant this time. How much did you pay for the repair of the head gasket ??
 

Spipa

Active member
Joined
Jul 18, 2019
Location
Netherlands
TDI
Mk 7 GTD
I have a DPF every 300-350 km, the loss of coolant this time is not related to DPF. It looks like the care is using the coolant this time. How much did you pay for the repair of the head gasket ??
It cost me €1630 to replace the head gasket and water pump and they also had to fix the cilinder head, but I didn’t take it to a vw dealer since they quoted me more than double that price.
 

mm-rocco

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Jul 31, 2019
Location
Netherlands
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MK7 GTD 2016
It cost me €1630 to replace the head gasket and water pump and they also had to fix the cilinder head, but I didn’t take it to a vw dealer since they quoted me more than double that price.

Thanks ! That is serious money !
 

BirdmanofTas

Member
Joined
Aug 13, 2019
Location
Australia
TDI
2013 Golf Mk7 Highline TDI
I have a DPF every 300-350 km, the loss of coolant this time is not related to DPF. It looks like the care is using the coolant this time. How much did you pay for the repair of the head gasket ??
Hi @mm-rocco sorry to hear your still having issues.. i would get your coolant checked for exhaust gases before going in to repairs.. if head gasket or egr cooler are faulty you will have detectable exhaust gas in your coolant.. if you dont, it could be mechanical or electrical coolant pump, or thermostat. but get the coolant checked first..
if you do have gases in he coolant, bypass the egr cooler as a first step and test the car before going straight into the head gasket.
 

AdrianC

Member
Joined
Jul 16, 2019
Location
Ireland
TDI
Golf VII GTD
Just an update guys.

I've done 600 miles approx (1000km) and absolutely no loss of coolant since i changed the heater core.
This mileage was done with a good bit of spirited driving through motorways and single carriageway - with a few regens in between.


Had a standing regeneration yesterday while i was at the supermarket and everything is good.
No Blowout.
 

Adyzds

Member
Joined
Aug 29, 2019
Location
Romania
TDI
Golf 7 2.0 TDI
Haven't replaced the heater core yet.
But I drove it 2-3k km and I was checking the DPF regeneration and afterwars I turned the heat to HI.

Result: not a single drop of coolant lost
 

Kennyboy993

Member
Joined
Oct 6, 2019
Location
Leeds
TDI
2014 Mk7 golf gt tdi
Hi guys - newbie here to the forum though certainly not to golf ownership.

I was hoping you could help me.

Recently acquired 2014 golf mk7 tdi and I’m having coolant loss problems which seem exactly like the symptoms described on here.

Car can go a long journey no problems and then suddenly - perhaps 2nd or 3rd long journey I’ll return to the car in the morning with large coolant loss. Down to a couple of mm visible in expansion bottle.

I’ve had the system checked and there’s no leaks - when it happens it leaves coolant in and around the area of the expansion bottle so I’m convinced it’s coming out of the lid under pressure somehow.

I’m 85% certain it’s only happening when my car does this regeneration cycle you speak of.

Can you tell me how I can force a regeneration cycle so I can advise my garage?

Also - my heating seems to work perfectly in both heat and AC cold, does this not prove my matrix is working ok?

Any advice gratefully received - I’ve just chopped in my lease for a car that I convinced myself would save us money and still be like a clockwork orange [emoji45]


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SkilledMilk

Member
Joined
Mar 31, 2018
Location
Glasgow
TDI
Leon MK3 (184) 2013
If you have all the symptoms mentioned, but it only loses coolant periodically and there's no mixing of oil and water etc then I think your problem is the matrix. My heater worked but was nowhere near as hot on 'HI' as another equivalent perol Leon in the family. After the change (~1200 miles ago) I've not lost any coolant and my heater is far hotter.

You could have the garage check for combustion gases in the coolant reservoir which would hopefully discount any head gasket issues. Myself and others in this thread have found that for whatever reason a standing/forced regen (not iniitated when driving) doesn't result in overflow of coolant, which is rather unhelpful for diagnosis!
 

nathanso

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Joined
Mar 31, 2019
Location
Redwood City, CA
TDI
2015 GSW TDI S 6M
Has anyone here with this problem inspected the silicate pouch in their coolant overflow reservoir to see if it has torn/leaked? This thead https://www.pistonheads.com/gassing/topic.asp?h=0&f=86&t=1780683&i=0 and other theads here on tdiclub make mention of this being a prime suspect in clogged heater matrices.
I proactively replaced my car's reservoir as described here http://forums.tdiclub.com/showthread.php?t=501125 Surprisingly, the reservoir costs only around $10 and it can be swapped out in under an hour with the help of a turkey baster to empty the coolant.
 

Kennyboy993

Member
Joined
Oct 6, 2019
Location
Leeds
TDI
2014 Mk7 golf gt tdi
If you have all the symptoms mentioned, but it only loses coolant periodically and there's no mixing of oil and water etc then I think your problem is the matrix. My heater worked but was nowhere near as hot on 'HI' as another equivalent perol Leon in the family. After the change (~1200 miles ago) I've not lost any coolant and my heater is far hotter.

You could have the garage check for combustion gases in the coolant reservoir which would hopefully discount any head gasket issues. Myself and others in this thread have found that for whatever reason a standing/forced regen (not iniitated when driving) doesn't result in overflow of coolant, which is rather unhelpful for diagnosis!


Ok cheers - I’ll recheck heater power on full blast.

I also need to do more testing then as I’m assuming my coolant loss is happening after the engine has been switched off.

I did 2 identical trips, the first didn’t lose any, the second lost almost entire expansion vessel - only thing is the time I realised was the next morning when I came back to the car. Annoyingly it as the only trip I didn’t check the car immediately after the trip - however coolant low warning light wasn’t on though was in the morning.


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DrSchultze

Member
Joined
Jul 15, 2019
Location
Denmark
TDI
Audi A3 2.0 2013
Remember to check all the vents, the heat seem to go bad in the left side before the right side.

When I had the problem, the coolant level didn't always drop immediately after a blowout, but instead waited until things cooled down, and coolant was sucked back into the system.
 

Theo95

New member
Joined
Sep 9, 2019
Location
Romania
TDI
Golf 7 2.0 TDI
Hi guys,

I also changed my heater matrix and after 2 regens I can confirm that the issue is solved, I had no blowouts. This felt like a never ending nightmare. Thank you!
The bottom of the expansion tank just gets a little bit wet to the touch, but I think that's normal due to condensation and high pressure.

What do you think, if the heater matrix got clogged up, wouldn't the main coolant radiator also be partially clogged? Is any of you suspecting something else than the silica bag to be the root cause for this?

@Kennyboy993 With forced regenerations my car was not blowing out coolant. Maybe it needs to do the full cycle. Before changing the heater matrix my car was blowing cooler air on the right side. I used a VCDS and I saw that on the right side there were 45°C and on the left side there were 55°C. I haven't checked the values since, but now I don't feel any difference in temperature.
 

Kennyboy993

Member
Joined
Oct 6, 2019
Location
Leeds
TDI
2014 Mk7 golf gt tdi
Ah ok thanks guys - that would explain why I can’t find any coolant loss after a journey, only the next morning...... mine must be happening on cool down also.

Tried my heating on full blast today - it couldn’t get above 49 degrees blowing out when specialist used a temperature torch type device.

Vw specialist is quoting me for new matrix tomorrow- is going to be painful [emoji37]


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