I have a 2000 audi a6 2.8 Quattro. I replaced both radiator hoses. Including other various cooling hoses, reservoir, and cap. I thought that would fix my leak. I was wrong. The car still leaks. I flushed the coolant with just distilled water before I replaced everything. Can anyone chime in and let me know what a few other things could be leaking. I hope it is not the water pump. Because I had it replaced about 40,000 miles ago along with the timing belt and thermostat. The oil looks good. So I dont think the head gasket is messed up. The car does not overheat. But I have to keep adding coolant and water. Could the water pump gasket have gone out? Or maybe the auxilary water pump? How hard is it to replace the heater hoses? I am trying to eliminate this headache before it gets any hotter in Texas.

 

I don't think the 2.8 has an aux pump - Maybe someone can clear this up..

Two potential places - resivor tank and back of the motor.

 

There's another potential leaking spot and that sob is hidden. It is the back of the thermostat housing.
The rear/main pipe coming into it is pretty much held in place tight only by a rubber O-ring. The ring can wear out over time pretty easily as is subjected to constant heat/cold changes. The coolant would sip out and trickle on top of the valley pan (straight down under the exhaust manifold). From there, the most likely place to "evacuate" when it overfills the area is toward the edge of the tranny.

Also, the pipes to the back of the heads have O-rings as well. If those get worn out and start leaking you should be able to see traces of coolant down the rear of the head(s).

I'm not saying that those would necessarily be "your" potential leaking sources, but you never know and you can chek'em out.

 

I have not replaced the heater hoses yet. But I want to replace them this week. Does anyone know if they have a special connection to the engine? Do i have to take the intake off to get access to the heater hoses?

 

Both of'em slide onto the coolant pipes and are secured with clamps.
One of them is connected to the pipe running into the back of the water pump housing. The other one is connected to the rear main pipe.
I think just taking off the throttle body will help you tremendously, otherwise is a really tight place, full of wiring harness(es), EGR valve, etc.
I think you can access them easier with the throttle body off, and you may not need to remove the manifold.

 

Provided your 2000 Quattro doesn't have a different routing for the hoses, here's what you look at:
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Good luck

 

I have currently replaced every cooling line. Still leaks in middle of engine by snub mounting bracket. I even replaced the metal cooling line on oil pan. I found the auxilary water pump on pasenger side where the lower radiator hose connects. I just want to see if i am missing something. I really dont want to replace my timing belt again. Where is the thermostat on the 2.8 v6? Can I replace the water pump by removing the drive belt, power steering pump, and timing covers.

 

There's you thermostat housing (front side - offset and above the alterantor):
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As far as the "leak in the middle of the engine", you may want to check the top of your valley pan, see if there's any collant pooled over there (under the manifold)
Here's what I'm talking about:
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that coolant pipe on the left side of the picture (let's call it passenger side), right over the edge of the valley pan cover, runs exactly in the back of the T-stat housing.
Since at the end has only a rubber O-ring edging that opening, the sucker can become leaky.
Maybe this is your problem.

 

Here's a closer pic...mind not the comments...lol
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You can see the pooled liquid over there, but mine was coolant mixed with oil.

 

I know I went overboard with the pics, but hopefully it illustrates better what I was talking about:
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Truth be told, I hope this isn't your problem because you'll have to take the manifold out in order to replace that o-ring.
If unfortunately it is, make sure you order also the "Main Rear Pipe to Cylinder Heads O-rings".
You may not need them, but you'll have to remove the pipe from the heads anyway