Coolant blown out from expansion bottle

Candellara

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Joined
Jun 17, 2019
Location
UK
TDI
2013 Golf GT
As an append to this, the reason i'm unconvinced the matrix is blocked is that after a simple flush - the heating system works exactly as VW intended. If the matrix was blocked - this wouldn't be the case.

My latest thoughts are that some component is causing air to be ingested into the cooling system - thus causing the heater matrix to airlock (no heat from vents) and the pressurising of the system (water being expunged from coolant bottle after long runs). This seems to only happen after long runs or after a hundred or so miles. When i "flush" the matrix - it expels all of the air, causing the system to work correctly until the next "cycle" when air is ingested into the cooling system

After some reading - EGR cooler? or EGR valve must be suspect. Is this possible?
 

GreenLantern_TDI

Veteran Member
Joined
Feb 27, 2014
Location
Iowa
TDI
2015 GOLF SEL
As an append to this, the reason i'm unconvinced the matrix is blocked is that after a simple flush - the heating system works exactly as VW intended. If the matrix was blocked - this wouldn't be the case.
My latest thoughts are that some component is causing air to be ingested into the cooling system - thus causing the heater matrix to airlock (no heat from vents) and the pressurising of the system (water being expunged from coolant bottle after long runs). This seems to only happen after long runs or after a hundred or so miles. When i "flush" the matrix - it expels all of the air, causing the system to work correctly until the next "cycle" when air is ingested into the cooling system
After some reading - EGR cooler? or EGR valve must be suspect. Is this possible?
If air is in the system VCDS has a procedure to purge the air from the system.
 

mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
As an append to this, the reason i'm unconvinced the matrix is blocked is that after a simple flush - the heating system works exactly as VW intended. If the matrix was blocked - this wouldn't be the case.
My latest thoughts are that some component is causing air to be ingested into the cooling system - thus causing the heater matrix to airlock (no heat from vents) and the pressurising of the system (water being expunged from coolant bottle after long runs). This seems to only happen after long runs or after a hundred or so miles. When i "flush" the matrix - it expels all of the air, causing the system to work correctly until the next "cycle" when air is ingested into the cooling system
After some reading - EGR cooler? or EGR valve must be suspect. Is this possible?
Good post, good thinking. In the beginning i could only think of the heater matrix. yesterday i had a long drive and used torque pro to monitor the coolant temp during and just after the dpf proces....the coolant stayed between 90 and 92 celcius. So the coolant is not really being boiled during and after the dpf proces and the blow-out can not happen because of the heat. So it looks something else is pushing out the coolant, i would think of hot air from a egr cooler. the egr cooler part cost about 350 euro and about 6 hours work, a bill in total of 800 - 900 euro.

Maybe a little crack in the egr cooler ???
 
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DrSchultze

Member
Joined
Jul 15, 2019
Location
Denmark
TDI
Audi A3 2.0 2013
@DrSchultze We are very interested in hearing your findings, no more blow out's ??? Do you notice in difference in oiltemp and coolant temp ?? We all look forward to hear form you :)
I have just returned from a week of hiking in the Norwegian mountains without my computer, but I used my car to get there. :)

I haven't lost any coolant on the trip, so I consider the problem solved by replacing the heater core.
The trip is ~1700km in total, of which ~500km is highway.
I didn't do any detailed logging, but kept an eye on the oil temp from time to time, and it never went above 115 degree C, and seemed to hover around 110 degree C.

Just went for a drive and paid attention to the heating.. the vent all the way to the left produced so much heat that it hurted when I put my hand for a long time against it.. the vent all the way to the right produced no heat at all eventhough I put the temp on maximum for both driver and passenger side.. the more I went to right, the less heat came from the vent.. so it looks like my heating is also showing problems even without dpf regen..normal?
This was the exact symptoms I had, before heating just failed completely.

Last weekend i did a test with the heating. Just after the DPF-proces i turned on the heating to max and drove for about 10 minutes then i stopped and checked the engine bay, coolant reservoir. The coolant in the reservoir raise almost near the top far above mex but did not blow out. Hopefully this information helps with solving the puzzle..
Turning the heat to max, would probably compensate for a heater core with a reduced flow, by removing extra heat from the system, so this makes perfect sense to me.

I'm confident that the problem in my case was that the partially blocked heater core, caused a reduced flow through the EGR cooler. Because of the reduced flow, water would boil in the EGR cooler during DPF regen, and push water out of the heater core (and the expansion tank). It would not push the water out of the cylinder head, because of the check valve in series with the EGR cooler.

Before my vacation I did see a tiny bit of coolant disappear, but I'll have to monitor it over a longer time frame, to make sure that I actually have a problem.
 

mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
I have just returned from a week of hiking in the Norwegian mountains without my computer, but I used my car to get there. :)

I haven't lost any coolant on the trip, so I consider the problem solved by replacing the heater core.
The trip is ~1700km in total, of which ~500km is highway.
I didn't do any detailed logging, but kept an eye on the oil temp from time to time, and it never went above 115 degree C, and seemed to hover around 110 degree C.



This was the exact symptoms I had, before heating just failed completely.



Turning the heat to max, would probably compensate for a heater core with a reduced flow, by removing extra heat from the system, so this makes perfect sense to me.

I'm confident that the problem in my case was that the partially blocked heater core, caused a reduced flow through the EGR cooler. Because of the reduced flow, water would boil in the EGR cooler during DPF regen, and push water out of the heater core (and the expansion tank). It would not push the water out of the cylinder head, because of the check valve in series with the EGR cooler.

Before my vacation I did see a tiny bit of coolant disappear, but I'll have to monitor it over a longer time frame, to make sure that I actually have a problem.

@DrSchultze Thanks for letting us know the results. 1700km without this problem sounds very good to me !

Is your engine the 184HP (135KW) type CUNA ??? How often, after how many kilometers do you have a DPF-regen ???

Thanks again !
 

DrSchultze

Member
Joined
Jul 15, 2019
Location
Denmark
TDI
Audi A3 2.0 2013
Is your engine the 184HP (135KW) type CUNA ??? How often, after how many kilometers do you have a DPF-regen ???

Thanks again !
I haven't been monitoring DPF regen systematically, but it seems to be around 400km between.

It's the 150HP engine, but the heater core seem to be the same for most VAG cars from 2013 to 2017.
 

mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
Hopefully my problem will be resolved soon as well. My local VW dealer will execute Tpi 2040004/9 "Prüfplan zum Kühlmittelverlust beim EA288 Dieselmotor". I hope they can find the part which is causing the blowing out of coolant. The investigation only cost about 200 Euro.
 

Spipa

Active member
Joined
Jul 18, 2019
Location
Netherlands
TDI
Mk 7 GTD
Hopefully my problem will be resolved soon as well. My local VW dealer will execute Tpi 2040004/9 "Prüfplan zum Kühlmittelverlust beim EA288 Dieselmotor". I hope they can find the part which is causing the blowing out of coolant. The investigation only cost about 200 Euro.
Can you explain what ‘Tpi 2040004/9‘ means? Some kind of recall?
 

mm-rocco

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Netherlands
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MK7 GTD 2016
Can you explain what ‘Tpi 2040004/9‘ means? Some kind of recall?

No Recall :) It is an instruction from VW to troubleshoot coolingleaks for the EA288 Engine (including "our" CUNA Engine). It should include the EGR Cooler and the cylinderhead. I specially asked them to also check the heatermatrix.
 

Spipa

Active member
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Jul 18, 2019
Location
Netherlands
TDI
Mk 7 GTD
No Recall :) It is an instruction from VW to troubleshoot coolingleaks for the EA288 Engine (including "our" CUNA Engine). It should include the EGR Cooler and the cylinderhead. I specially asked them to also check the heatermatrix.
Oh alright! So when will they check your car? And isn’t your car still under warranty? You still have to pay?
 

mm-rocco

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Jul 31, 2019
Location
Netherlands
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MK7 GTD 2016
Oh alright! So when will they check your car? And isn’t your car still under warranty? You still have to pay?

Well, Yes ! I have. If i did not have warranty i would probably still follow this route. Otherwise you could still end up with replacing good parts. I you can replace the heater matrix yourself i would do that first. I will not because i am not a mechanic. I will book a date tomorrow, hopefully for next week.
 

mm-rocco

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Jul 31, 2019
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Netherlands
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MK7 GTD 2016
@Spipa Did you receive a quotation for replacing the heater matrix ??? How much will it cost to replace ??
 

Spipa

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Jul 18, 2019
Location
Netherlands
TDI
Mk 7 GTD
@Spipa Did you receive a quotation for replacing the heater matrix ??? How much will it cost to replace ??
Just went to my mechanic, he told me that he had two other GTD’s visit him this year for the exact same problem, he has replaced the heater core on them both (after some other work has been done by the VW dealer) but they still have the coolant overflow problem. He advised me to not put any more money in it and just sell the car lol
 
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mm-rocco

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Jul 31, 2019
Location
Netherlands
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MK7 GTD 2016
Just went to my mechanic, he told me that he had two other GTD’s visit him this year for the exact same problem, he has replaced the heater core on them both (after some other work has been done by the VW dealer) but they still have the coolant overflow problem. He advised me to not put any more money in it and just sell the car lol

That does not sound very promising. I would say bad advise :) Next week they will troubleshoot my car, hopefully they will find it. I am suprised your mechanic does not know about the TPI which is an instruction from VW to resolve the problem. Are you sure this is a real VW Dealer ??
 
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BirdmanofTas

Member
Joined
Aug 13, 2019
Location
Australia
TDI
2013 Golf Mk7 Highline TDI
Hi all, i am glad i found this thread, i have a 2014 Golf Highline Mk7 TDI with same issue only blows coolant after a highway run, had the dealer check and after replacing coolant tank and cap said the Head Gasket must be blown and quoted $4000 AUD.. instead i have replaced the engine complete with a known good engine (5o,oooKm) and still have the issue.. only parts left original after engine swap are radiator, heater matrix, alternator and starter motor.. i did buy the car cheap because of this issue, so have been happy to spend to fix the issue.. i have a new Nissen updated (B code) heater matrix on order from the US, so will advise if this fixes the issue or not.. parts turn up in about a week so heres hoping..☺
 

mm-rocco

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Jul 31, 2019
Location
Netherlands
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MK7 GTD 2016
Hi all, i am glad i found this thread, i have a 2014 Golf Highline Mk7 TDI with same issue only blows coolant after a highway run, had the dealer check and after replacing coolant tank and cap said the Head Gasket must be blown and quoted $4000 AUD.. instead i have replaced the engine complete with a known good engine (5o,oooKm) and still have the issue.. only parts left original after engine swap are radiator, heater matrix, alternator and starter motor.. i did buy the car cheap because of this issue, so have been happy to spend to fix the issue.. i have a new Nissen updated (B code) heater matrix on order from the US, so will advise if this fixes the issue or not.. parts turn up in about a week so heres hoping..☺

Woh...what a story ! Thanks for sharing this with us. Are you sure the EGR Cooler was not re-used from the faulty setup ??? What about the heating, is your car getting warm in the winter (do you have a winter ?? :) ) What is your engine-type , horsepower ?? Is the new engine the same type or newer ??


Sorry for all these questions, i am so fed up with this problem ! I hope replacing the heater matrix will resolve yours !
 
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mm-rocco

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Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
The last two DPF REGEN's i turned on the heating to "HI" (open windows) and awaited the DPF REGEN to finish and the exhausttemp was brought down from 700 Celcius tot 250 Celcius. Afterwards i checked the coolant and the reservoir was still full !!!


I am 99% sure the heatermatrix is the faulty part but i cannot rule out yet that it is not a combination of two failing parts. The EGR Cooler could be the second part.
 
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BirdmanofTas

Member
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Aug 13, 2019
Location
Australia
TDI
2013 Golf Mk7 Highline TDI
Woh...what a story ! Thanks for sharing this with us. Are you sure the EGR Cooler was not re-used from the faulty setup ??? What about the heating, is your car getting warm in the winter (do you have a winter ?? :) ) What is your engine-type , horsepower ?? Is the new engine the same type or newer ??
Sorry for all these questions, i am so fed up with this problem ! I hope replacing the heater matrix will resolve yours !
the EGR Cooler was not reused.. (so i have a spare everything just about), i had noted that the heating sometimes seemed not to work (its winter here at the moment) i had flushed the heater matrix once via the firewall and got the heat working again, but it did stop again., it is the CRBC engine 150Hp, and the replacemenmt is the same engine type, out of a slightly newer car.. mine had 100000Ks the replacement has about 50000Ks..,
i believe the new matrix will fix it, as there is very little left to change, so should be a good test.. :)
 

mm-rocco

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Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
the EGR Cooler was not reused.. (so i have a spare everything just about), i had noted that the heating sometimes seemed not to work (its winter here at the moment) i had flushed the heater matrix once via the firewall and got the heat working again, but it did stop again., it is the CRBC engine 150Hp, and the replacemenmt is the same engine type, out of a slightly newer car.. mine had 100000Ks the replacement has about 50000Ks..,
i believe the new matrix will fix it, as there is very little left to change, so should be a good test.. :)

Thanks ! Make sure you flush the coolant system as some some debree in the system might clog new the heater matrix again. I found this topic yesterday, there is as link somewhere to an external PDF-instruction form VW about this as well. http://forums.tdiclub.com/showthread.php?t=481260&page=8


This would explain that the problem is back in month's or years after replacing the heater core.....
 

BirdmanofTas

Member
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Aug 13, 2019
Location
Australia
TDI
2013 Golf Mk7 Highline TDI
the EGR Cooler was not reused.. (so i have a spare everything just about), i had noted that the heating sometimes seemed not to work (its winter here at the moment) i had flushed the heater matrix once via the firewall and got the heat working again, but it did stop again., it is the CRBC engine 150Hp, and the replacemenmt is the same engine type, out of a slightly newer car.. mine had 100000Ks the replacement has about 50000Ks..,
i believe the new matrix will fix it, as there is very little left to change, so should be a good test.. :)
I should have mentioned, that the car had just had a new EGR Cooler replaced as well by the dealer, just prior to my buying the car, so it still had the coolant expansion issue after the new EGR cooler....
 

mm-rocco

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Jul 31, 2019
Location
Netherlands
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MK7 GTD 2016
Just went for a drive and paid attention to the heating.. the vent all the way to the left produced so much heat that it hurted when I put my hand for a long time against it.. the vent all the way to the right produced no heat at all eventhough I put the temp on maximum for both driver and passenger side.. the more I went to right, the less heat came from the vent.. so it looks like my heating is also showing problems even without dpf regen.. I have a service scheduled on the 23rd, I will ask them to replace the heater core and let’s hope it solves it once and for all..

I also noticed that after testing the vents when I pressed on the ‘off’ button for the heating, there was still some hot air coming out of the vent, is that normal?

@Spipa Did you replace the heatermatrix, any results yet ??
 

AdrianC

Member
Joined
Jul 16, 2019
Location
Ireland
TDI
Golf VII GTD
Keeping a close eye on the heating vents on the dash..

Engine running at normal operating temperature..
Heat from the left and centre console, cold air from the right vents..
Mines a Right Hand Drive..
This really is a puzzle.

Heater matrix? Possible. How can air/pressure be introduced in a closed coolant system?
Egr Cooler or Valve, Maybe..
Radiator? Unknown..
The DPF Regeneration holds the answer..


This is frustrating.
 

mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
Keeping a close eye on the heating vents on the dash..

Engine running at normal operating temperature..
Heat from the left and centre console, cold air from the right vents..
Mines a Right Hand Drive..
This really is a puzzle.

Heater matrix? Possible. How can air/pressure be introduced in a closed coolant system?
Egr Cooler or Valve, Maybe..
Radiator? Unknown..
The DPF Regeneration holds the answer..


This is frustrating.



This is frustrating indeed :)

:) :) Thanks for keeping this topic alive, i would be great if we can look back at this topic in some time.

To my opinion your heater matrix is not working as it supposed to do, i would replace the heater matrix. I found this document where is explained that you should flush the system properly. https://drive.google.com/file/d/0ByxgazxO4YLZV0hyTm1OVm1tNE0/view
In this document the EGR is mentioned. My engine is not mentioned in this document, aluminium rust, flux and the EGR do ring a bell......

I checked the coolant temp directly form the CANBUS before and during the blowout, it stays between 90 en 92 celcius. The boiling of coolant might be in a zone of the coolingsystem where there is no tempsensor. Could it be possible that the heatermatrix acts as a reverse radiator, not cooling down quickly but warming up quickly. Could coolant (liquid) expand in volume if you heat it up with 500+ celcius so that it pressurizes the coolantsystem with over 2 BAR and cause a blow out.



NEXT :)
 
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DrSchultze

Member
Joined
Jul 15, 2019
Location
Denmark
TDI
Audi A3 2.0 2013
This is still an interesting thread, and apparently a quite common problem. And I'm really disappointed with my local Audi authorized workshop who pretented that they didn't know anything about the problem, when I called them. Instead they were eager to start swapping head gasket, waterpump, intercooler, EGR cooler, cylinder head etc. asking ~220$/hr. + parts at my expense. :mad:

Heater matrix? Possible. How can air/pressure be introduced in a closed coolant system?
Egr Cooler or Valve, Maybe..
Radiator? Unknown..
The DPF Regeneration holds the answer..


This is frustrating.
Your heater matrix is definitely (partially) blocked. Air gets into the system when the coolant boils in the EGR during DPF regen. It boils because the EGR cooler relies on continuous flow via the heater matrix.
 

AdrianC

Member
Joined
Jul 16, 2019
Location
Ireland
TDI
Golf VII GTD
Thanks Schultze..

So I’ve decided to take the plunge and change the heater matrix.
Have my car booked in for Thursday 29th August with my local independent garage. He did is training with VW and is a decent sort.
He has changed a couple of these in the past so knows the score.
Seems to be in agreement that the core is blocked.
So I have him instructed to follow the correct flushing procedures before removing the core
He will flush the system twice.
Reckons it will take a few hours and estimated a price of around 400€ Euro - parts included.

Here’s hoping.

I will update all when the job is done.
 

SkilledMilk

Member
Joined
Mar 31, 2018
Location
Glasgow
TDI
Leon MK3 (184) 2013
Been monitoring this thread for a while now, as I had the same issue as described; loss of coolant through the overflow on the expansion bottle but only after a DPF regen.

Started happening to me about a year ago and I just learned to live with it as my local mechanic couldn't be certain of the problem and I wasn't willing to sink lots of money and end up with no solution.

I have a Leon with the CUPA engine from late 2013, currently with 225,300km and I started noticing the issue at around 161,000km. In interim servicing I had the garage check for oil/water contamination and pressure test the coolant circuit, each time coming back with no evidence of head gasket failure. I was able to narrow the overflow down to just after a regen using the VAG DPF app and an OBD dongle. Coolant temperature never went over 90 and oil was in the range of 90 - 110 depending on driving conditions. One thing that i had noted was that the heater set to 'HI' didnt really provide hot air (it was warm but not overly so).

To cut to the point, based on DrShultze's experiences I decided to order up a Nissens heater matric and have a go at changing it myself. On removal of the old matrix it was clear that the channels in the Nissens matrix are quite a bit larger than those of the outgoing matrix. There was also considerable resistance to me blowing air though the old matrix compared to the new one.

I have since driven around 1500km and have had no overflow and I am tentatively considering the issue fixed. Will be interesting to see if any others come back with the same findings and resolution.

Edit: forgot to mention that the heater set to 'HI' is now almost unbearably hot, so would indicate that coolant circulation is much improved.
 
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AdrianC

Member
Joined
Jul 16, 2019
Location
Ireland
TDI
Golf VII GTD
Thanks for the update Skilled Milk.
Places like these are great to talk and knock ideas around at little to no cost. I could have spent, like others did, hundreds, even thousands on fixes that were not necessary. Head gaskets, pumps, coolers etc.
The heater core is more than likely the cause, so replacing it correctly will be the difference I hope.
 
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