[VAC] Refrigerator work

[Aecal@xxxxxxx]

Hello,
Thanks to all for the responses on the hitch set up. Now, sooner or later I'm 
going to get back to working on the refrigerator. I haven't gotten involved 
in the gas in the trailer yet but I did make some ice after changing a heater 
and plugging in. I also changed the thermostat since the heater was on 
constantly. There was no change. It just seemed to want to be on or off. 
Adjusting the thermostat just changed where in the range of the control it 
turned on. I have no particular reason to trust either of the thermostats. I 
have parts left over from a former dealer shop. It seems they saved some 
faulty things for some reason. I get a certain amount of pleasure from 
tinkering around with this stuff. This is a good thing to tell myself as I 
waste time by stubbornly avoiding asking advice. So let me ask this, does it 
make any sense to think that a refrigeration unit is less efficient because 
of age and would require being heated constantly to maintain proper 
temperature for food storage? I did the turning it upside down thing. OR, 
should I assume because it works well enough to make ice that it is okay. I 
have a new old stock refrigeration unit to replace it with. Whether that 
could be just as bad because of age I have no idea. It has a nice paint job 
and maybe I might as well try it since I have it.
 Having read the service manual on the subject of making that replacement I 
came upon references to "Thermal Mastic" and "Permagum". Does anyone know 
where I can get these things?
Best Regards,
Erik Murray