HVAC questions

[Wyle E. Coyote]

First of all, I haven't had my MB long, and being that this is my first, the following questions might sounda little basic, but I need to get to the bottom of the problem I'm having.

It seems to me that the car doesn't heat up inside very fast, even when it's not that cold outside. I've read my owner's manual and I kinda understand how the controls work. But since day one that I've had the car, I've been running a piece of cardboard in front of about 1/2 the radiator to help it. It seems to not get that hot on the gauge. So here are my questions:

1.) How high is the normal operating temp supposed to be? And where does the danger zone begin? (Normally is runs at 40-60. It got up to just over 80 once after running down the highway at 75+mph for about 30 miles, but it cooled right back down)

2.) Could the fact that I don't have an A/C condenser in front of the radiator be making the radiator "too efficent"? (I had another car that I had to run a hotter thermostat in because of that problem)

But then I got to wondering if I even have a thermostat. So while I'm tinkering around the car tomorrow I might just have to go get a gasket and see.

Anyway, I wanted to ask the general consensus here what they think and have experienced with this. Thanks in advance for your help.