Audi S6 C6 Thermostat problem + heater core

A6 All/ S6 All
#1

Hello,

I waited to become a member of this forum from summer and yesterday I wrote why isn’t my account approved… :slight_smile: FINALLY I may tell! :slight_smile: I bought my first “super-luxury” car. Have owned before hand 1x Q7 V8 TDI, 1x Q7 3.0 TDI, 1x A6 C6 Allroad and now an S6 C6. All have been much fun, but I miss the V8 TDI the most, I managed to chip it to over 300kw and that was a beast. Now I’m dreaming to get an Q7 V12 :slight_smile: :slight_smile:

Now onto the problem.

VCDS is a must with these cars.

Code: “thermostat for mapped cooling j265 open circuit”

This means that my whole assembly (water pump + thermostat) is maybe bad, but the only code is with the thermostat. I live in Europe and this summer was very hot and nice. It didn’t overheat and didn’t seem to get any problems and I didn’t care about that problem. Now when it’s almost October and we are getting -0C, the car won’t get hot to 90C.

I see that I can only change the thermostat also, but is it a good choice? Should I change the whole assembly? I will be doing it DIY and make pictures all the way. I’ve got myself ELSA also and it’s good to have.

The thermostat code should be 079121115BA (https://bit.ly/2Ih65nC).

Heater exchanger core has some problems too now.

Code: “Coolant circulation pump v50”.

Found a guide that you can clean it. Why would you clean it, you may ask? That part is much more expensive that water pump and thermostat assembly. I’m getting warm/hot air inside my cabin, so I don’t know why that code is throwing up.

Has anyone opened up their car? What should I do? Replace only thermostat? Do I need to disassembel all my front? How to refill coolant without the pump etc?

#2

Hi There buddy

I have an 07 S6 Avant with exactly the same issue. I took it for a thorough car wash the other day and they jet washed the bottom of the engine due to a slow oil leak and now my car wont go over 70 degrees most of the time. It does jump to 96 occasionally as I saw on the vcds history! I m getting the same fault code “thermostat circuit open” J265 and also fould the coolant valve fault in the history like you did. What happened in the end how did you fix it?

Many Thanks in advance
Harry

#3

Hi

I only changed the thermostat. Only bought a new thermostat, didn’t need a water pump. You can do it below the car.

Took me maybe 1 hour in total.

#4

When you replaced the stat did your coolant pump code go away automatically?

#5

Hi

I think that it didn’t magically disappear. If I remember correctly, one full scan with VCDS (Ross-Tech) and “Clear DTCs” did the trick.