2005 M2 Overheating Condenser

Hi all. I have a 2005 Freightliner M2 that I am working on the ac system. I have replaced a blown line, some seals, drier and expansion valve. I have vacuumed and filled the ac up to the proper level. The issue I am having is the ac turns on, but the high side pressure quickly rises so the compressor turns off and the truck never cools down inside. I have found out if I run water on the condenser for a few seconds when the pressure rises, then the pressure stays in check, and thus the cab cools perfectly. So essentially my issue is the high side pressure rises too much. That would mean the ac condenser is overheating, my question is why? While this is happening the fan clutch is barely engaged, and the fan is hardly spinning, however it doesn’t get much better when on the road, and the engine itself isn’t overheating. Thanks for any help

 

It is an air clutch, Horton part number 989336. So I am correct in assuming with the AC engaged this fan clutch should be both engaged and spinning considerably faster than a couple rpm?

 

Great thanks! I just wanted to be sure I was looking at a cooling issue, rather than a blockage internally or a bad condenser. I know where to start. Thanks a ton