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

Welcome to the forum.

The thermostat is a common failure on these cars as they tend to get stuck shut for some reason. Your code looks to be the code for the electronic heating element that acts to open and close the thermostat via computer control.

Getting an idea on the mileage on the car would help make more sense in giving direction. But its always a safe and smart bet to replace the entire water pump thermostat unit depending on age.

You will need to pull the front end off the car or at the very least put the car into service position. I would strongly remomend that you just pull the front end off to make sure you get a better chance to look over everything.

If your pulling the front end to do the water pump that’s a great time to do a carbon clean and to inpect your oil filter O rings.

#3

Hi and thanks!

It’s a 2006/11 car, so basically a 2007 model.

It has 223 000KM on its odometer but I don’t think it’s real. Bought it from a car dealer who told me that it was standing still for about 1 year, then the previous owner from Switzerland sold it to them and now I’m the new owner. The car dealer did change valve cover gaskets because they leaked.

When I was enjoying my car and the “supercar” feeling, then in about 2 weeks after purchase some anomalys started up. It started fine but when I was sitting and letting it idle, then I could feel how bad the motor was working. (Now I know that it’s not a good idea to let them sit and idle, just start and drive but not too aggressively).

I let a indie change my spark plugs, nothing was getting better. Started throwing “Misfire 2 Cylinder” and sometimes MIL also on. That’s when I started to research and got a good idea that maybe the injector is the problem. So because there were sometimes 10 Cylinder misfire too, I made the decision to change them both. When the indie opened my car, they took a picture and sent it to me in Facebook, THERE WAS NO CARBON BUILDUP and someone has been messing with the intake. One of the motors have been deleted from it, how is that possible?!

Before I let the injectors change, I did a compression test myself. All cylinder were almost indentical, from 12.8 bar (185 PSI) to 13.8 bar (200 PSI). Two were 12.8 bar, 4 was 13.8 bar and the rest were 13.0-13.7 bar. I think that the motors has been taken good care of and the cylinders are in a good shape.

Is there any manuals how to put the car in service position?

#4

sounds like they gutted the intake.

as for the service position, it’s pretty similar to the B6 A4 and other audis.

There 2 or 3 10mm nuts attaching the bumper to the front fenders that are accessible through the wheel wells.

Then a myraid of torx bolts under the bumper and up top. You can remove the bumper at this point, but need to disconnect the daytime running led strips and the headlight washers.

once that’s removed the rest will be straight forward.

#5

compression wise 190 or better is good. 185 isn’t bad but check those cylinders for misfires. If misfires go too long you will take out the cat and that’s exepensive as you need to drop the motor to get to the cats.

As mentioned it sounds like you have a gutted intake manifold. If that’s the case you can see misfires from a gutted intake as they don’t always flow well for cold start and idle conditions.

#6

Thanks for all the good words!

Can anyone give me some instructions on how to exactly change the waterpump and the thermostat or will ElsaWin also help me and give me a good idea on how to?

#7

If you can take of the front core support its very easy. Its right there on the front of the motor on the driver side.

#8

Hi,

I changed only the thermostat, it was easy to do when the car was standing up there. Now everything is O.K! :slight_smile: