Audi A8 air suspension problems

[express666]

Hello!
I am new to Audi, and have just bought an Audi A8 one month ago, 57reg, 3.0tdi Quattro, engine code ASB. There are a few confusions that I do not understand, I see the coolant temperature gauge always stay in the quarter mark when I switched the climate control on, it only go to the middle when I switch off the climate control, is this normal or should I change the thermostat. And the air suspension system should be adjusted manually, but the four mode in the car section on my MMI, and it stays in the automatic mode all the time, I tried to change to different mode, it does not have any responding, the two arrow stays on both side of the car symbol does not change at all. Is this normal ? The garage who sold me this vehicle told me the air suspension can only change when I driving, I notice when I switched on the jack mode, there is no change in the height of the vehicle, and it only change when I switched on the towing mode, it goes higher. The gap from the tyre to tyre housing is four fingers in front and two fingers on the back, I notice this does change from time to time.The car drives perfect. Thanks for anyone can help me!