P42 Reefers
The two reefers on our 1991 still do the job. Fridge keeps the beer cold and the freezer freezes water for ice along with other stuff. Here is what I did, but whether it helps, I'm not sure to what degree.
1. The original grey lid seal material still seems to work, but to help I added the self sticking foam 1/4" weather stripping on top of the grey material. That seems to have closed some gaps. I used the dollar bill test and it did show some spots where the lid was not making a solid seal.
2. As was mentioned earlier I inserted two small sink plugs into where the reefers drain into the shower sump. The purpose is to stop any air flow into or out of the reefer boxes. I remove the plugs periodically to let out a very small amount of water.
3. The freezer does accumulate a small amount of frost around the cold plate that builds up during the course of a year. I usually shut off, empty and clean out both units at the beginning of the season just so things remain fresh smelling.
4. I cut a piece of that 1/2" plastic wire coil stuff that some use under their bedding to allow air to keep moisture from forming and placed it against the wall in just the upper freezer section. It seems to help allow cold air between the freezer wall and foods so that foods remain frozen on both sides.
Our original AB units are on 24/7 year around. So far they still do the job. I had the freezer recharged when we took possession in 2002 and the fridge control module replaced DIY in 2003. I make it a practice of pushing down on the lid after closing just to make sure the lid seals.