Contaminated coolant

[GearGeek]

I need some advice on a potential issue with the coolant in my 16 plate Passat 2.0 TDI (43k miles).

My local VW dealer first noticed that the coolant was “dirty” when they had it in for service back in December. They kept the car back for a few days to investigate. They concluded there was no issue and they just flushed out the system and replaced the plastic expansion tank.

Since then I have been keeping an eye on it and the issue has been reoccurring. It’s been back to the same dealer 3 times and still the issue hasn’t been resolved. The steps taken at each visit so far:

1) Flush & replacement expansion tank
2) same as above
3) flush & replacement heater matrix

The car is currently with the dealer for the 4th time. The coolant discoloured to a brown colour after less than 500 miles after previous visit.

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Despite this, all the dealer has done is flush the system out again. They’ve road tested the vehicle and admit they can see that the coolant is discolouring. However, they are telling me that it is now within “acceptable parameters” so there is nothing more they can do.

As you can tell I’m not happy. I’ve asked to speak to the service manager when I go to collect the car on Monday. I’m concerned that there’s a potentially serious issue with the engine and I’m just being fobbed off. Am I overreacting or am I justified in pushing back on this?

Thanks for reading and sorry for such a long post!!