I have a 450 and the freezer quit. It seems that the pin valve into the evaporator got plugged as I couldn't get a charge, the evaporator inlet tube frosts up but the evaporator doesn't get cold. It is original and I thought to replace as it also needs a thermostat and fan, given its age of 23 years couldn't expect it to survive a lot longer. Anyone know how thick the insulation used was? Should I add interior insulation? Can't see without tearing up everything around it. I am arguing with myself about an evaporator vs cycling holding plate. Conversion thoughts? Sadly it worked perfect until I shut it down for quite a while. I am looking to move aboard shortly so a freezer matters.