Coolant blown out from expansion bottle

DrSchultze

Member
Joined
Jul 15, 2019
Location
Denmark
TDI
Audi A3 2.0 2013
I used this kit: https://www.ebay.co.uk/itm/254136111708

I think that all the tests with blue fluid are more or less the same, I'm no chemist but I don't think that there that many chemical reactions with CO2, that makes something change color from blue to yellow or green.

The difference in color between gasoline and diesel, must be due to some additional gas in either of them.

But what are the sensitivity of the test? Normally you wouldn'd carry out such a test, unless you suspect a blown head gasket, because of a mystery water loss or after the engine had overheated, and starting acting up, and in most cases you would just get a confirmation of the obvious.

But if the test is sensitive enough to detect that you popped a soda next to the expansion tank last week, it's really just an indication that you *might* have a leak somewhere. But I'm just guessing here ;)

It would be interesting to do the test on a known good engine.
 

mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
I am so glad I found this topic ! Hopefully we can solve the puzzle together !
I imported a MK7 GTD 2016 form Germany into the Netherlands with 93.000km in march 2019. I had to refill coolant quite a few times now and noticed that this always occurs on long drives (5 hour) and sometimes on shorter drives (1 hour) and only on motorways doing 100 – 130 KM/H (60 – 75 MpH).

I could not find any leakage, no coolant on the floor of the garage. We checked the car with VCDS and could not find any errors, we forced a DPF with VCDS and noticed there was coolant coming underneath the reservoir.

At first I thought the reservoir would be broken so I bought a new one. The reason there is coolant coming underneath the reservoir is because there is a small overflow pipe going through the reservoir. When the pressure is over 2 BAR the coolant is released through the pipe.

After the forced DPF and the loss of coolant I was convinced that the overpressure in the coolingsystem is related to the DPF. As I can not always drive around with a laptops and VCDS-cable I bought a bluetooth CANBUS connector and bought the app VAG DPF. This gives a dashboard with counters on the DPF process. This way I exactly know when the DPF starts and finishes.





My coolant temp on the dashboard stays 90 Celcius and my oiltemp is varying from 100 – 105. The DPF is done every 200 - 350 km. When i put the DSG in S-mode just after the DPF proces finishes and drive it more sportly i sometimes manage to not overflow the coolant, the coolant still rises almost to the cap but does not overflow.

I imported the car from a VW dealership and I still have warranty. I am allowed to let my dutch VW dealership to investigate the problem. But,……what to test, check, fix or replace ???
 
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bigb

Veteran Member
Joined
Dec 15, 2018
Location
Arizona
TDI
2015 Sportwagon S
My coolant temp on the dashboard stays 90 Celcius and my oiltemp is varying from 100 – 105. The DPF is done every 200 - 350 km. When i put the DSG in S-mode just after the DPF proces finishes and drive it more sportly i sometimes manage to not overflow the coolant, the coolant still rises almost to the cap but does not overflow.

I imported the car from a VW dealership and I still have warranty. I am allowed to let my dutch VW dealership to investigate the problem. But,……what to test, check, fix or replace ???
I don't have anything except that the dash coolant gauge is not an accurate way to measure coolant temp, I recently discovered that when I was monitoring it with Torque Pro. I saw the ECT range from 194 to 220F and the dash gauge never budged from it's straight up position which reads 200F. I am not sure how hot ECT would have to get before the dash gauge actually moves from center but I would suggest monitoring it with something else to get the true ECT.
 

mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
I don't have anything except that the dash coolant gauge is not an accurate way to measure coolant temp, I recently discovered that when I was monitoring it with Torque Pro. I saw the ECT range from 194 to 220F and the dash gauge never budged from it's straight up position which reads 200F. I am not sure how hot ECT would have to get before the dash gauge actually moves from center but I would suggest monitoring it with something else to get the true ECT.

Thx....this sounds like a more accurate reading, 90 - 104 celcius is not alarming yet but could be a great reading relating to the coolant blow out.
 

mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
Today i tested the interior heating, all the vents were blowing out very hot air. But when it was DPF de-generating again i noticed that the level of the coolant did not rise this time and there was no blow out of coolant. There must be a link between the two....driving around in the winter or in colder regions with the heating always on probably does not help with solving this solving as it does not occur or not that often.
 
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bigb

Veteran Member
Joined
Dec 15, 2018
Location
Arizona
TDI
2015 Sportwagon S
I paid special attention yesterday while I was on the highway to see if a regen would affect ECT, it wasn't really noticeable. Maybe 3 or 4 degrees F but that could have been the grade, or the outside temp but ECT definitely does not spike during a regen while driving.

When you forced your regen was it a standing regen? It would be interesting to watch ECT during a standing regen.
 

mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
I paid special attention yesterday while I was on the highway to see if a regen would affect ECT, it wasn't really noticeable. Maybe 3 or 4 degrees F but that could have been the grade, or the outside temp but ECT definitely does not spike during a regen while driving.

When you forced your regen was it a standing regen? It would be interesting to watch ECT during a standing regen.

Thx ! We did do a standing REGEN and the coolant was pooring out.
 

bigb

Veteran Member
Joined
Dec 15, 2018
Location
Arizona
TDI
2015 Sportwagon S
Thx ! We did do a standing REGEN and the coolant was pooring out.
Can you tell me how long does a standing regen take, and does it reset the counters as if it were a normal regen? Say if you were due to regen in about 10 miles but you forced it early, will the counters reset or will you get another one at the 10 miles?
 

mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
Can you tell me how long does a standing regen take, and does it reset the counters as if it were a normal regen? Say if you were due to regen in about 10 miles but you forced it early, will the counters reset or will you get another one at the 10 miles?

I think it took about 15 minutes and the counters will reset like doing an normal REGEN.
 

AdrianC

Member
Joined
Jul 16, 2019
Location
Ireland
TDI
Golf VII GTD
Good afternoon all,

A few more people posting the same problems I see. Hopefully we can get to the bottom of this sooner..

Been absent for the past while after a period of inactivity with Coolant Overflow.
Everything seemed to be going fine until this morning.

Just had my most recent coolant blowout after 500 miles and during regeneration as i was travelling back home..
Did not have access to VCDS as i was driving at the time..

Definitely notice a temperature change in the vents on the dash from drivers side to passenger side..

It has to be related somehow..
 

Spipa

Active member
Joined
Jul 18, 2019
Location
Netherlands
TDI
Mk 7 GTD
Hi guys,

So it seems like we can assume that the coolant overflow only happens during dpf regen. That makes me wonder if i bring my gtd to a tuner to deactivate the dpf through coding (without physically removing it) won’t that probably solve the problem?
 

DrSchultze

Member
Joined
Jul 15, 2019
Location
Denmark
TDI
Audi A3 2.0 2013
If it's possible to disable DPF regen through software, that would most likely be a bad solution. DPF regen happens when the filter is clogged with soot, and serves to convert the soot into ash. So if you disabled regen, you would end up with a completely clogged filter, and a car that wont run.

It's approx 1200km since I replaced my heater core, and I haven't had a boilout since. It's worth noting that when the boilouts started I still had heat from the vents, but it disappeared over time, as the heater core vent from sligthly clogged to completely blocked.

It does still seem to be using up water, and I suspect that the EGR cooler has been damaged from overheating because of insufficient flow of coolant.
 

Spipa

Active member
Joined
Jul 18, 2019
Location
Netherlands
TDI
Mk 7 GTD
It's approx 1200km since I replaced my heater core, and I haven't had a boilout since. It's worth noting that when the boilouts started I still had heat from the vents, but it disappeared over time, as the heater core vent from sligthly clogged to completely blocked.

It does still seem to be using up water, and I suspect that the EGR cooler has been damaged from overheating because of insufficient flow of coolant.
Hi Schultze,

Could you tell me how much time there was between the first time coolant boiled out and the moment you replaced the heater core?
 

DrSchultze

Member
Joined
Jul 15, 2019
Location
Denmark
TDI
Audi A3 2.0 2013
Could you tell me how much time there was between the first time coolant boiled out and the moment you replaced the heater core?
Somewhere in the order of 5-6000km. over about 3 months. The first few times I didn't took much notice of it, as it only happened every 800-1000km.

But I'm unsure if the boilout happened on every DPF regen in the beginning, or if I just had a lot of passive regeneration at that time.
 

Spipa

Active member
Joined
Jul 18, 2019
Location
Netherlands
TDI
Mk 7 GTD
Somewhere in the order of 5-6000km. over about 3 months. The first few times I didn't took much notice of it, as it only happened every 800-1000km.

But I'm unsure if the boilout happened on every DPF regen in the beginning, or if I just had a lot of passive regeneration at that time.
So if i understand correctly, you only lost heat from the vents during dpf regen? Or also when the dpf was not regenerating? I have this problem now for like 20.000km and I honestly did not notice loss of heat from the vents, probably because of the weather because I did not need to turn the heat on for the past months. I will check the heat later today after work. Did heat stop coming from all the vents?
 

DrSchultze

Member
Joined
Jul 15, 2019
Location
Denmark
TDI
Audi A3 2.0 2013
So if i understand correctly, you only lost heat from the vents during dpf regen? Or also when the dpf was not regenerating? I have this problem now for like 20.000km and I honestly did not notice loss of heat from the vents, probably because of the weather because I did not need to turn the heat on for the past months. I will check the heat later today after work. Did heat stop coming from all the vents?
In the start I didn't noticed heating problems, but on the other hand the heat wasn't on.
Then by chance I discovered that heat disapeared from time to time, which I later liked to the loss of coolant, this took some time as it't didnt boil out enough coolant to trigger the coolant warning, and the heat recovered when the car had been parked for a while and cooled down. So my first theory was a stuck actuator, in the ventilation system.

Later on I started noticing thumbing noises and boiling coolant in the heater matrix, and missing heat in the driver side. At this time when the boiling happened, I pulled over and popped the hood, but coolant level looked normal as long as the engine was hot, but after cooling for a few minutes, level dropped, as coolant was sucked back into the system, and heating recovered.

But not all of the vents failed to blow hot air, in the end heating just failed permantly in the driver side, and was almost non existent in the passenger side, as the core was completely blocked.
I tried flushing the core, but without success, since at this time the heater core was filled with flakes of "something" beoynd recovery.
 

Spipa

Active member
Joined
Jul 18, 2019
Location
Netherlands
TDI
Mk 7 GTD
Alright Schultze, thanks for de detailed responses. I will check the heating during the next dpf regen, curious if my heating shows the same problems as you described. Could you send me a link or picture of the heater core you purchased?
 

DrSchultze

Member
Joined
Jul 15, 2019
Location
Denmark
TDI
Audi A3 2.0 2013
I bought a Nissens cooler, mostly because that was what my parts pusher could deliver instantly, they also seem to be ready available on e-bay for few $$. And given how easy it was to replace, I had no problem buying something not VW. The connections to the core is quite sketchy, but it seems to hold water.

The replacement was like this guy describe: https://www.youtube.com/watch?v=WTODVb8SRVA The procedure in a Golf is most likely the same.

I have some pics of the old and new core here: https://photos.app.goo.gl/XkNkRSFJtp44C1aY9

Also a log of active DPF after the core was replaced, and some of the flakes of "something" that came out of the old heater core.

The channels in the new core was noticeable bigger than in the original.
 

mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
I bought a Nissens cooler, mostly because that was what my parts pusher could deliver instantly, they also seem to be ready available on e-bay for few $$. And given how easy it was to replace, I had no problem buying something not VW. The connections to the core is quite sketchy, but it seems to hold water.

The replacement was like this guy describe: https://www.youtube.com/watch?v=WTODVb8SRVA The procedure in a Golf is most likely the same.

I have some pics of the old and new core here: https://photos.app.goo.gl/XkNkRSFJtp44C1aY9

Also a log of active DPF after the core was replaced, and some of the flakes of "something" that came out of the old heater core.

The channels in the new core was noticeable bigger than in the original.

Great info ! Thanks ! Was it this easy on your Audi ??? Anyone have done this on a MK7 GTD allready ???
 

mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
Hi guys,

So it seems like we can assume that the coolant overflow only happens during dpf regen. That makes me wonder if i bring my gtd to a tuner to deactivate the dpf through coding (without physically removing it) won’t that probably solve the problem?

Removing or codig out the DPF is not allowed in the Netherlands :) Milieudelict, APK-afkeur. What are your symptoms on loosing coolant, how often do you have to refill ??
 

Spipa

Active member
Joined
Jul 18, 2019
Location
Netherlands
TDI
Mk 7 GTD
I bought a Nissens cooler, mostly because that was what my parts pusher could deliver instantly, they also seem to be ready available on e-bay for few $$. And given how easy it was to replace, I had no problem buying something not VW. The connections to the core is quite sketchy, but it seems to hold water.

The replacement was like this guy describe: https://www.youtube.com/watch?v=WTODVb8SRVA The procedure in a Golf is most likely the same.

I have some pics of the old and new core here: https://photos.app.goo.gl/XkNkRSFJtp44C1aY9

Also a log of active DPF after the core was replaced, and some of the flakes of "something" that came out of the old heater core.

The channels in the new core was noticeable bigger than in the original.
Alright thanks a lot! I will let you know if my heating shows the same problems as you described. I hope that replacing the heater core solves the coolant overflow permanently, please let us know if it seems that it has not been solved.
 

Spipa

Active member
Joined
Jul 18, 2019
Location
Netherlands
TDI
Mk 7 GTD
Removing or codig out the DPF is not allowed in the Netherlands :) Milieudelict, APK-afkeur. What are your symptoms on loosing coolant, how often do you have to refill ??
I know, but desperate times call for desperate measures. I have been driving with these problems now for 20.000 km and spent close to €2k to solve the coolant overflowing. It happens like once every 3/4 weeks for me and only after a highway drive. When it happens i have to refill with about 200/300 ml of coolant.
 
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mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
I know, but desperate times call for desperate measures. I have been driving with these problems now for 20.000 km and spent close to €2k to solve the coolant overflowing. It happens like once every 3/4 weeks for me.



€2k is a big loss. What did you replace for this money ???
 

Spipa

Active member
Joined
Jul 18, 2019
Location
Netherlands
TDI
Mk 7 GTD
€2k is a big loss. What did you replace for this money ???
Yeah it is. I got ripped off by the dealer, they told me it was the head gasket and the cilinderhead had to get fixed. They did this and replaced the expansion tank and everything was back to normal according to them. But clearly not.
 

mm-rocco

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Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
Yeah it is. I got ripped off by the dealer, they told me it was the head gasket and the cilinderhead had to get fixed. They did this and replaced the expansion tank and everything was back to normal according to them. But clearly not.

This is very good info, sorry about the rip-off ! My GTD is from 01/2016, the newer GTD models supposed to have a different heater core. Keep me informed on your next steps, maybe we can help eachother with finding a independent VW Specialist who can replace the heater core for "normal" money. 2000 for the headgasket with labour is not to bad.......
 

AdrianC

Member
Joined
Jul 16, 2019
Location
Ireland
TDI
Golf VII GTD
I know, but desperate times call for desperate measures. I have been driving with these problems now for 20.000 km and spent close to €2k to solve the coolant overflowing. It happens like once every 3/4 weeks for me and only after a highway drive. When it happens i have to refill with about 200/300 ml of coolant.
2k seems like a lot of money for a job that didn't work. I had been suspicious that this was the case with my own but, if it was indeed a cylinder head then the coolant would be pressurizing once the engine is turning over.
This would happen all the time.

But this problem seems to be intermittent so I am ruling out a head gasket.
 

mm-rocco

Well-known member
Joined
Jul 31, 2019
Location
Netherlands
TDI
MK7 GTD 2016
I sent my german VW dealer a description of the problem with all my findings and i have asked them approval to let my dutch VW dealer do the investigation. Hopefully i can get fixed/solved this way.


What about the rest of you ?? How are going to tackle this problem ???
 

DrSchultze

Member
Joined
Jul 15, 2019
Location
Denmark
TDI
Audi A3 2.0 2013
Great info ! Thanks ! Was it this easy on your Audi ??? Anyone have done this on a MK7 GTD allready ???
Yes took it apart a few days after, to check for leaks. Used less than 1 hour to get access to the heater core, and assemble everything again.
 
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