You are almost there, I can assure you there is more air in the system. I have been exactly where your are now, frustrated and getting low on spare coolant. Raise up the coolant tank, fill it full, jamb a stick on the accellerator holding the revs at 2500 and bleed that core discharge hose one more time.

On mine it seemed the pressure came up in the core in waves, sometimes sending a stream of coolant out the bleed hole with great pressure, then the pressure would drop and no coolant came out.......this low pressure time is when I pushed the hose back on as I think air was actually being sucked back in!

good luck, and by the way I can't believe Audi is clueless on this issue.

 

I've got the same problem. I will be preforming this trick this Christmas and will let you guys know the outcome. ITs 30 degrees in the bay area and without heat its COLD!

 

I think Im getting to the bottom of the problem...because of the no heat at idle I decided to change the water pump to rule out one more potential problem and to inspect the condition of the old one. Upon removal I noticed it was in perfect condition and it was the newer updated impeller (not the problem). So I put everything back together and used a vacuum air lift system to fill the coolant.
Well all excited about the airlift system to find out that I had know heat what so ever!!
So back to square one.....
Bleed, bleed, bleed, bleed, bleed......oh yeah.....more bleed!!!!
An hour and a half at 2500 RPM, Bleed, cap on....cap off...cap on...Bleed.
Finally got heat, even hot at idle for 30 minutes.
Next day...still good, car warmed up and defrosted at idle...WoooHooo!
Next day...cool air at idle Bleed again.....hot air at idle again
Three days....so far so good.....fingers crossed, ill keep ya posted!

 

getting it bled properly is a b1tch sometimes

However, are you sure your not getting air in somehow?

 

Fail, Fail, Fail....
out of no where the good ole' 1.8t decides to not produce heat today.
back to square one.

I was able to get heat if I took the reservoir cap off while the engine was hot and when it was about to explode all over me I screwed the cap on and I got heat for about 15 miles of driving than back to cool.

I cant find a reason that I would be getting air into the system. no leaks that are visible, oil is clean and free of signs of antifreeze. Engine temp is still perfect.

I Just don't get it

 

This happend to me also, check the hose for leak at the flange. Run your finger under the discharge hose at the core and check for coolant, mine was leaking and I figure air was getting in. Look closely at the flange coming off the core, it has a raised/flared end and another flare up farther towards the firewall. The hose has to be pushed on over both flares, push the hose all the way on and set the clamp somewhere in the middle of them.

Have a look and report back!

 

All hoses were tight and no leak from the discharge hose.

New solution!!!

In the morning before I started the car I decided to try a cold temp bleed. (why not?)

I pulled the top hose out to the bleed position on the heater core. Than I took the small tube off the reservoir and held the tube closed with my thumb. Than I put my mouth over the nipple on the reservoir and blew slowly until there was a steady small stream coming out of the bleeder hole. With the free hand slide the bleeder hose back closed. Than I brought the tube with my thumb on it close to the nipple with my mouth on it and did a fast connection back together.

Topped the reservoir off and put the clamp back on the top tube and I have had heat for two days now.

I'm going to try it again to get out anymore air but I think this dangerous idea works.

 

hehe...