Cooling fan 300C
 

I just recently installed a new radiator and everything worked great until I found out I had been advised the wrong antifreeze. So I drained and flushed the radiator. I had a hard time getting the petcock valve back in the radiator. I ended up taking the cooling fan out in order to get the valve put back in. Filled the radiator the proper way and when it was time for the fans to kick on they are running super loud. I had to reposition the fan on the bottom to sit properly on the cradles on each side and figured that was my problem. Well it wasn't, and the fans are still running super loud. Does anyone have a clue as to why this is happening now? I've never had a problem before with them.