I have a 2000 audi a6 2.7t and it is running warm. It does not overheat but it will go to the line after the middle and stay there. I just changed the water pump a month ago. Checked all my fluids and nothing was low. Can someone please shed some light on what this might be please. Thanks!

 

You might not have not burped the cooling system and now have an air lock. There are two bleed points in the system in the 3.0, you need to check on yours to see what the procedure is.

 

I didn't want to burp the system after I repalced TB water pump, thermostat etc. My car would be one tic above the middle line when I first started it for a few minutes. What I did is un screwed the cap of the expansion tank every time I parked the car. It bubbled up every time (it will because of the temp change) but after 4 or 5 times it drew out the air in the system out and its all good now.

There is a chance you may have the wrong thermostat too. Always make sure to check the part number. Did you change the thermostat with the pump?