The Reason The Suction Line Is Frosting
Is that the capillary line has come loose from the suction line [ you can clearly see this in your picture ] that is frosting over. Originally the little 1/8" cap tube was soldered to the outside of the larger suction line, this part of the sealed system is called the Heat-Exchanger, the warm cap tube coming from the condenser is soldered to the suction line to complexly cool the liquid refrigerant heading into the evaporator and in the process the cap tube warns the suction line slightly which keeps it from sweating and or frosting.
Whirlpool had problems in the 80s with the cheap solder they used when attaching the cap tube to the suction line failing and allowing the cap tube to come loose.
The CURE is to shut down the ref and clean the suction line and allow to to completely dry, then use really good 3M electrical or good aluminum tape and tightly tape the loose cap tube to the suction line, this should stop the sweating and frost back problem. You may have to partly remove the rear mounted condenser to get at the lines all the way to where they go back into the ref. After you do this you can put some foam insulation over most of the tubing to replace what you have to remove.
Often times when the cap tube comes loose like the first sign of problems is the ref does not maintain proper temps and it ends running more than it should.
John L.
