The flattened hose you were feeling was probably your condensate drain for the a/c. What is your engine temp running at about five minutes into your ride and also at operating temps? If your engine thermostat is either stuck open or missing altogether, your engine will take quite a long time to circulate and heat the cooling water, and it still wouldn't seem that warm when using the heater in the car.
Just a Thought,
"Tell me and I will listen, Teach me and I will learn, Show me and I will accomplish, Involve me and I will succeed."
'84 300SD 256,000 Gold on Brown (Mileage Award)
'86 300E 246,000 Blue on Tan