I can't help you regarding oil as I live in San Diego and have no experience with those temps. Regarding the oil filter, yes you can add one. In my manual, it's part # 110813-001 (oil pump housing). I believe it's the same housing, just drilled and taped to accept the hollow filter mounting stud, part # 110825, along with an oil return hole. I also have a couple of non-filtered Quincy pumps and the housing looks exactly like the filtered housing except for as I described above, including the filter sealing surface and the raised center casting where the hollow stud would be located.
I found this on another page of this site. Sounds like its doable. Problem is finding one thats cheap.
" Oil filter
Quincy 325 compressors can be found with or without an oil filter housing. While all other parts of the compressor appear to be the same, the main difference is the front bearing carrier. This part does not allow for an oil filter housing, or filter to be installed in most cases. In order to convert your "non filtered" unit to a filtered one, this carrier must be changed. ALL 325 compressors are pressure lubricated, wether it has a filter or not, the filter just adds longevity to the compressor and oil change intervals. To my knowledge, all new 325 units ship with filter housings."
As for the control, im confused on it cause i did pull the paperwork and it shows all 3 control methods but none look like whats on mine. It comes from the bottom of the tank, feeds a check valve, then some part which i can identify. It doesnt look like any valve quincy shows to use. it has a hole in the side of which i can see in. Theres 2 set screws inside but the only way to access them is to pull the entire thing apart. I can post a pic if needed.
