Condenser vibrates and makes noise??

[RickF350]

Sometimes the condenser in my 05 F350 will vibrate and make a grinding sound. So far this only happens after the truck has sat for a few days or is cold (ie 20F) and only during the first second or two of the first compressor cycle. If you want to see what I'm trying to explain, PM me your E-mail and I'll sent you a video of it.

So far Ford has cleaned the lines and or orifice, adjusted the compressor clutch and took out some refrigerant ,but it still vibrates. Tomorrow they want to overcharge the system.

So, does anyone know what is wrong my AC?

[bustech81]

I had an issue with this problem last year, however it was on an e- chassis. what was happening was the pump was slugging liquid. only until the pump built some heat did the liquid flash. In large bus systems we implement things like liquid line solonoids and condenser check valves to keep this from happening. what i did to correct was replace the accumulator/drier, then two new reed valve plates in the pump. ignored recomended charge level and did the old fashoned way. got compressor superheat to 12 degree's with 20 degrees of delta t. Don't remember exact charge however. havent had a problem since. good luck