SMac770

Well, when you replace the oil filter, there's going to be some loss of oil, as a decent bit will be inside the filter. That's why sometimes you'll see specs for how much oil to put in when changing the oil filter vs not changing. I just assume the spec 4.9L oil capacity for our motor assumes a new, thus empty, oil filter.

That coolant pump you pictured in the link is the afterrun pump, not the main coolant pump. The afterrun pump is electrically driven, and does not contain any temp sensor or thermostat. Did he determine the problem was not the main coolant pump but actually the afterrun coolant pump, and maybe coolant was just being sprayed onto the main coolant pump? The afterrun pump sits just forward of the main pump, iirc; it would have been to the left of all those hoses in your original picture in this thread. Pierburg is an OEM for both pumps in the B8.0.

Auxiliary (aka after run) coolant pump for B8.0 (this unit is driven by electricity):
https://parts.audiusa.com/p/Audi__/4...06H965561.html
Pierburg is an OEM for that part:
https://www.ecstuning.com/b-pierburg...06h965561~pie/

Main coolant pump for B8.0 (this unit is driven by a belt connected to the rear end of the left balance shaft):
https://www.ecstuning.com/b-genuine-...e/06h121026dd/ (this has a better pic of the unit than the audi parts site)
Pierburg also is an OEM for this part:
https://www.ecstuning.com/b-pierburg...h121026dd~pie/

So different part numbers, and they look very different.
The purpose of the after run coolant pump is to continue pumping coolant to the turbo after the engine has been shut off. Otherwise, the heat sits in the turbo and can cook the oil sitting in it.

sasikals26

Thanks for your detailed explanation @SMac770 !

I am sure that he had removed the below part from my car and showed me and confirmed that the water pump has gone, and then he mentioned I will replace it with Pierburg water pump and use the thermostat and sensor from my car itself.



From my new Image, I can see he replaced the highlighted part + there is one metal piece over there.



Further, I drove 50-60 KM after the replacement and went to the garage and he confirmed everything is okay and gave me 1 year warranty for labor+parts.

SMac770

He may have concluded the housing was generally fine, it was just a problem with the gasket for the impeller and just replaced that piece, retaining the original housing, and therefore the original thermostat. Hard to say without a clear pic of the parts that came out of the car and did not go back in. But if the problem is resolved, then who cares too much.

sasikals26

Agree :-) , but my concern is I paid 1150 PLN/300 USD for this repair(Part+labor)!

However, thanks for all your response and time, I really appreciate it.