My newest Benz is on it's way to me, but today, the car started only blowing luke warm with the temp on the warmest setting.

The local Benz dealership said the DUO valve is out.

My question is if the car is ok to drive approx 8 hrs if the climate control is off.
Thanks

 

I would not drive it with luke warm air at highest setting.Something is wrong in the cooling system and an engine running under temp is as bad as an engine running over temp.Get it checked,run the diagnostics,make sure the coolant temp is in the proper operating zone.
Dealers will tell you anything,once the car is off the lot it is your problem.