First off, here's the car I bought: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4549279201 . The two important parts regarding the a/c system are:

Items of note that have been replaced in the last few years include the radiator, the glow plugs, and the A/C compressor/associated system (new refrigerant compatible).

And:

The power antenna does not work properly nor does the A/C cool properly (needs recharging).

Now let me say, I know that sometimes (or oftentimes), the a/c needs more than a simple recharge, and I went into this knowing that it could need some repairs. Also let me say that I'm no car mechanic, but I am able to do basic tasks given the right tools.

I have no idea how to tell exactly what parts of the a/c system have indeed been replaced and what has not. I do believe the guy, he pointed out a lot of little things, I doubt he would lie about replacing parts of the a/c system. I do suspect the hoses weren't replaced, they appear to have the adapters put on them that you'd get with the R134a conversion kit (I can take pics if needed). I bought one can of refrigerant with leak sealer, and several plain cans. I followed the instructions to the "T". Start the car, engage the a/c, shake the can vigorously, connect the hose, hold can upside down and wait (yes, I did turn the screw to open the can and again to let it flow through). Now, I have since read that one should NOT hold the can upside down? That it should be held right-side up else it could cause damage? I swear though, the can says to hold it upside down, I even double-checked the instructions. So now, I'm confused.

Also, when I was putting in the first can, the pressure gauge spiked up to the yellow area (not red, but close). It went down into the green within a minute or less. The subsequent 3-4 cans I put in, it went barely into the blue ("filled") area, but down back to green ("low"). It is not putting out cold air, feels like outside air.

I've called around town, no one will work on a Mercedes. I'm hoping it's something simple I can diagnose and fix myself, or worst case something I can diagnose, buy the parts for, and take it somewhere and just say "this goes here".

I can take pictures if needed, can also take a video if you need to hear it running. I am not certain that the compressor is kicking in, but I have noticed at least more than once, that after I turn on the a/c the motor will sound like it's suddenly under a bit of a load, like any other car would after turning on the a/c. Sorry I can't be more descriptive than that.

BTW, I don't have any service manuals for it yet other than what it came with originally, but plan on going to Clarksville sometime this week or next and will try to remember to look for one (I live in a pretty small town, no Wal-Mart, AutoZone, Advanced Auto, etc.; NAPA is about 15 miles away).

Thanks!