Strange AC Problem - Slow to start, sometimes

[Redliner911]

Hi guys, for us here in Arizona, spring was last Tuesday and hell is about to begin, so I would like to get this solved.

Cliff Notes version: The AC will not blow cold air at startup until I rev the engine to about 4krpms. This seems to get the radiator fan turning and thus the AC compressor engages.

Long version:
I've been lurking on these forums for two years now and they have been super helpful fixing things, but I've finally come across a mystery that searching this forum has not solved. My air conditioning works great... once it starts running. But sometimes it takes as long as 5 minutes before it will blow cold air. Before that it just blasts me with hot air. Other times it will start up within 30 seconds and work great. After searching the forums, I found a lot of similar AC problems are related to the accessory fan in front of the radiator. However, when I went to check it, I realized my '04 x5 4.4i does not have this fan at all! I found one mention of some x5 not having an accessory fan, but I don't know why this is and what it means for the AC system. Now heres the thing, I did notice that the puller fan (the fan behind the radiator) was not running at startup so I revved the engine to about 4krpms at which point the fan turned on and the AC started working immediately. So right now whenever the AC will not run at startup, I sit there revving my engine a bit until the compressor will engage. It's not the most elegant solution, so I would like to find the root cause. It's not very classy to be revving your engine whenever you get in and I think some people might think I want to race them, lol. I did have the dealership look at it about 8 months ago and they found a leak, I believe it was the condensor. It was repaired and the system was re-charged, so I am pretty sure there are no leaks and the system is charged. The issue to me is getting the compressor to start running at startup. Any ideas?