Hi everyone. My car has about 34k on the clock and is 4 years old, Octy 1.6 TDI. Two months ago car was at the dealership for a total of about 10 days as I drove the car in due to coolant issue. My entire expansion bottle was corroded, coolant was brown (no oil) and bellow min level. They have flushed the system several times and they filled it with new coolant, in total they did that at least 2 or 3 times (multiple flushes + new coolant) but problem returned very quickly.

They swapped the thermostat, expansion tank and also in the end EGR (so they say). Now, coolant is super cloudy and slowly changes from pink to brown color after only 1.5k miles and two months (no traces of any particles inside but its hard to tell as its cloudy). I think that for now level of coolant is steady. When I open the expansion tank I can hear a hiss and then if I sniff it, it smells (to me at least) on exhaust  fumes (btw I told them that before).  I tried looking at the tank with engine running and I see no air bubbles. If you torch the tank after opening at night you can see something as a faint smoke/dust particles from within expansion tank (not sure if that is normal).

 

One evening it happened that after car was parked more than 24 hrs, I opened the expansion tank to check for coolant state and heard hiss. Next morning I checked again and heard a his AGAIN but the car was not touched since the last opening of the tank in the evening, not event contact was given by the key. I told them that story as well.

 

I am suspecting on gases from engine block entering somehow coolant, either through block or sealant between. Told them that as well but they denied that as the reason.

 

Now I am trying to prepare myself to go back to the dealership with same problem.

 

I should mention that car is now under 5th year of warranty that is given by dealership, 4 years where on skoda and distributor in my country (above fix attempts were done under that 4year warranty) and even though I have warranty I suspect they will be even more negligible as fix comes out of their pockets now (i assume). 

Any advice or help is welcomed.

 

This is how coolant looks now from outside, they fitted new expansion tank as well and yet you can clearly see orange/light brown film residue on the tank and coolant level drops. When coolant is still a bit warm, you cannot see those two plastic dips inside for sensor. When cool, cloudy look kinda sets down a bit...at least is seems so.

Prepare for a major engine repair. Cylinder head gasket at least.

Would it be advisable to pursue that under warranty or should I just ditch the car? I am seriously leaning towards the latter...

Does look like the head gasket gasket has failed, would need a "sniff" test (i syringe with a fluid in it is put over the header tank and the bulb pumped drawing in the fumes, the fluid is normally blue but turns yellow if hydrocarbons are present in the coolant)  to confirm, if the head gasket has failed it's a big job to repair but should/is a warranty job.