Worldwidebeagle

Hello Brain Trust:

Wife's 2011 A6 3.0T thermostat failed. 65000 miles. Doing the replacement this weekend

I have read MANY great threads on replacement here and elsewhere. TONS of great advice, photos, parts lists, you name.

Water pump is late model all metal, so I do think there is no need to replace that. I plan on doing the accessory belt while there.

ECS recommends replacing the INFAMOUS Audi coolant sensor - that's easy.

ANY other parts while the SC is off?

Anyone have great (or even not so great) wisdom from your replacement? THANKS

twopedalwarrior

Only sage advise I can offer, have a six pack or beer handy

QToo

A little experience here. Not sure if you completed this project already or not. I have an 09 3.0T and did the thermostat to get the car back on the road after a failure. Ended up with a small leak from the cross pipe to t-stat connector so had to take it apart again and did the water pump as well.

Many great writeups and a few videos that I located. My advice would be to remove the hose that connects to the TOP of the crossover pipe. On the second go round, I left it on as I didnt think I would be in that area. Ended up snapping the connector off and had to purchase a whole new crossover pipe, ouch.

The space between the front of the engine and the radiator is VERY tight. I also ended up taking the entire bumper and other bolts off so I could tilt the front end forward. Gave quite a bit more space for my fat fingers to work.

Hope that this helps you or someone else tackling this project. Not too difficult overall, just time consuming.

Worldwidebeagle

Thanks for your reply. I am still into the project. As with EVERY Audi repair project, half way in, I found other things to fix. I noticed the vacuum pump was half covered in thick oil film. Researching it, it was a telltail sign of failure. Removed pump (easy) it and found it was totally filled with motor oil. New pump on the way. Also replacing the two short SC rubber coolant hoses.

Was the leak you mentioned on the stub pipe in the middle of the crossover that fits into the thermo housing? Did you replace the O ring? I have a new special O ring made for that pipe, as well as new special o rings for the left and right side of the coolant pipe. I did remove the overflow tube to the top of the coolant pipe. - I can see how it would be easy to break.....

Car has 65k and metal water pump with metal impeller - so i was advised NOT to change the water pump. No signs of leaking or weeping at all.

I found many write ups, including a very new one on YouTube where the guy does not speak, but does excellant methodical work. When I took over the old thermo housing, the pieces flew up at me from the big spring inside -- major failure.

I found I did not need to put the car into service position. The new YouTube I mentioned even gave the length of the extensions needed to get at the coolant crossover pipe bolts.

Did you replace the main accessory belt? I have only spent a minute to try to get it off. Looks like i need to loosen the SC belt idler to let the acc belt slip out.

I will be back at it when parts arrive. THANKS!

QToo

The leak was at the center stub going to the t-stat. The first time, I reused the o-ring on the crosspipe but couldnt make it fully seat. Didnt think that this would be an issue, but there was a very slow drip. When I did the water pump and needed to replace the crosspipe, that already had an oring on it.

What was the special oring for the stub pipe? A new part or did you get somewhere else? If from a dealer, please let me know the part number if you have it and I can look into it.

Worldwidebeagle

The coolant pipe to t-stat housing o ring is 06E121119C; the two o rings at the ends of the coolant pipe to the cyl heads is 06E121119E.

Make sure you put some pure silicone paste on the o rings before sliding them on.

When the car was still under warranty, it had a coolant leak somewhere under the a/c compressor. Could only be seen with a mirror.

Have you done pressure test? Good pressure testers with adapters for VW/Audi can be borrowed from Autozone for free.

RostyVyg

Check if your car falls under workshop campaign 19H3, - you might have your thermostat replaced for free:

These are the vehicles effected

U.S.A.

2010-2011 A6
WAU_ G_FB_AN001608 - WAU_G_FB_BN030581
Production date: May 28, 2009 – October 01, 2010

2011 Q7
WA1_G_FE_BD000447 – WA1_G_FE_BD003507
Production date: August 13, 2010 – September 30, 2010

2010-2011 S5 Cabrio
WAU_GAFH_AN005249 – WAU_GAFH_BN006387
Production date: June 10, 2009 – September 29, 2010

2010-2011 S4
WAU_G_FL_AA007653 – WAU_G_FL_BA055169
Production date: June 05, 2009 – October 04, 2010


CANADA

2010-2011 A6
WAU_ G_FB_AN002163 - WAU_G_FB_BN030081
Production date: May 27, 2009 – September 30, 2010

2011 Q7
WA1_G_FE_BD001023 – WA1_G_FE_BD003508
Production date: July 13, 2010 – September 30, 2010

2010-2011 S5 Cabrio
WAU_GAFH_AN005314 – WAU_GAFH_BN006375
Production date: June 12, 2009 – September 30, 2010

2010-2011 S4
WAU_G_FL_AA007954 – WAU_G_FL_BA052350