Need a data point of comparison (aka - how does this work in YOUR car?).

The car is my 84 300SD (W126).

When I start the car with A/C "on" and I let the climate control do it's thing - the A/C really doesn't do anything but blow air as the car idles in the garage. The air temp stays ambient (warm) as I sit and idle after start up. As soon as I get a little forward motion, down the alley even, air temp starts to drop like the A/C just got a wake up call.

So.... does the compressor need to build pressure in the system, or is engine RPM / speed needed to get the climate control going or is this just a symptom of needing a charge? Or is this normal?

Once I'm cruising down the road the car cools great, icy cold on the freeway. Temp guage never gets too hot etc. A/C at a light might not cool as effective (fan speed will have to kick up for example if I'm idling in traffic), but I figured that was because no air was going across the condensor. My main question is should the A/C kick-in quickly (within say 30 sec) of start up?

__________________
~shell
As of 2/2010:
2001 CLK55 0o\=*=/o0
13.6 @ 106mph
10K mi
1984 300SD
260K mi and going and going...
97 S600
46K miles
1991 Sentra SE-R (extremely dorked with)
www.se-r.net