Coolant lost during DPF active regeneration

[Tovarnik79]

Coolant lost during DPF active regeneration OCTAVIA 3 CKFC, 2.0 TDI 110kW 2013

 

Hi a have a problem with coolant lost. I lost every time whole coolant tank trough the coolant overpressure lid  - every 500 – 600km in one time.

I changed lid, then also coolant tank to the new one – no effect.

I found, that I lost coolant just when DPF active regeneration start – every 500 – 600km in one time.

Engine have to be hot and I lose it during the trip. Temperature sensor shows 90°C. No overheating.

 

I visited Skoda service, they did coolant system pressure test – OK.

Then they start DPF active regeneration and diagnostic – OK – the engine was probably cold when they start and no drive.

 

They diagnostic everything and told that  it is OK. Also told, if coolant pump problem, it should showed at temperature sensor, because overheating….

 

But coolant sill missing according description.……. Every 500 – 600km, in one time, whole coolant tank trough the coolant overpressure lid, every time detected DPF active regeneration (min rotation speed 950/min few minutes), Sensor temperature 90°C – no overheating detected

 

Do you know, what could be the reason?

 

Thank you for help J

[Gabbo]

If I understand correctly, you can drive for several days/weeks with no problem & no coolant loss.

Then after one drive (where you suspect DPF regen is active) the coolant is lost through the overflow in the coolant bottle ?

Do you have a coolant level low warning afterwards?

 

My first though was an air-lock, blockage or coolant pump/thermostat problem but I would assume Skoda should have already looked at these possibilities.

Is your cooling fan working as this might cause high températures if it didnt operate correctly.

 

Are you sure that it is occurring when regeneration is active (every 500-600km would seem to coincide with normal regen time).

Im not sure with the O3 but with many cars, the idle speed is increased when the engine is very hot to pass more cold air through the engine & increase the pump speed/coolant flow.

[Tovarnik79]

Hi, it is correct, I can drive for several days and no problem. Then after on drive lose whole coolant bottle – before was filled to higher level.  I detect coolant low level warning tomorrow, I every time detect active DPF regeneration (950/min and fuel consumption 1,1liter/hour)  which should come according EA288 manual every 495 miles…. Important is that the panel show temperature 90°C…… Cooling FAN is going when DPF regeneration is activated.  According Skoda service is it normal and should be everytime activated. According explanation, if coolant pump problem, the overheating should be detect with temperature sensor. But temperature is constant. They told that in the system are more sensors, but did not detect problem…. Then where is the problem.  :-)

[classic]

As I understand it the cooling system on these engines is quite complex with different cooling microcircuits to improve warm up and thermal efficiency.

They definitely have an egr cooler, perhaps this has a fault which shows up under regen ?

Thats my guess anyway ! 

[Breezy_Pete]

@James@Pentagon_Seat; 

Any thoughts?

 

(James is a man I would drive a long way to see if I had a problem with my car that I couldn't solve).

[LittleGap]

Did you get to the bottom of this problem? I have a similar problem on my mk3 2.0 tdi ckfc.

 

[Tovarnik79]

Hi. I still have this problem. Nobody directly know the reason. I got contact to Skoda engine productin. I will call there next week. I will see.... nobody here about this problem before..

[Ootohere]

You are in the Czech Republic just tell the Dealership to get a grip get Skoda CZ on the case.

It is July and you posted in March.

Pith taking going on someplace and it looks like at the Dealership you attended.

[Steveyboy]

On 07/07/2018 at 15:56, Tovarnik79 said:

Hi. I still have this problem. Nobody directly know the reason. I got contact to Skoda engine productin. I will call there next week. I will see.... nobody here about this problem before..

 

Hi. Did you ever get to the bottom of this as I seem to have the same problem, even tho the water pump has been changed

[Steveyboy]

On 06/07/2018 at 22:21, LittleGap said:

Did you get to the bottom of this problem? I have a similar problem on my mk3 2.0 tdi ckfc.

 

 Did you ever find the source of the problem?

[Tovarnik79]

Hi, service changed  coolant, coolant pump and  seal under head an the problem continue :-(. 1200 Eur invested for nothing, I do not know the source of the problem.

[Saints92]

https://forums.seatcupra.net/index.php?threads/loss-of-coolant-from-expansion-tank-and-i-dont-know-why.445350/

 

Give this thread a read and see if it sounds familiar. Final post explains how they resolved it, if it is the same symptoms.

[Kizotina]

On 26/03/2019 at 16:28, Tovarnik79 said:

Hi, service changed  coolant, coolant pump and  seal under head an the problem continue :-(. 1200 Eur invested for nothing, I do not know the source of the problem.

Did you solve the problem? 

[Tovarnik79]

HI, did not solved it but i found this forum.

 

http://forums.tdiclub.com/showthread.php?t=483783&page=2

 

Where is?

My latest diagnosis is that right after regeneration, the EGR valve opens (if you are driving it under light load or lift the accelerator pedal - during regen is allways shut) and blows very hot air from after DPF into EGR cooler. There it boils because of insufficient/restricted water flow trough heater matrix which is right after EGR cooler.
I read somewhere that early 2013 models had too thin pipes in heater matrix and it could be easily partially clogged. Later models have updated version of matrix.

 

I changed driving stile. I do not brake with the engine and do not use automatic speed control when regeneration come. And no problem. 

[Koprcopr]

Hi, I'm facing exactly the same problem. The car Octavia iii is from 2013, TDI 2.0 110 kW. I drove now two cycles of DPF regeneration (2x cca 500km) with diag-unit plugged in.  During reg. process it pushed out significant amount of coolant. Other values were in order. Intercooler 44deg.C, fan 75%, EGR closed 0%, coolant 91deg.C, Oil temp. till 100deg.C, .... It may be really the point, that EGR opens to early and hot gas overheats the cooler. Thank goodness i do not accept "head down" proposal in service. Did you solve the issue only by changed driving style ?