Wow!! thanks for those great inputs!! I'll ask one more advise please?

I went to a corner benz mechanic and he suggested plugging the hose from the duovalve going to the engine so that the hot coolant would not enter.

I do not need the heater anyway so plugging it with some rubber or whatever would be fine??

I tried disconnecting the duovalves but the aircon now blows weak air. So i just returned the connection since this was not right.

Hmmmm. Would plugging the hose be OK???