Quote:Thanks Bruce. It is a complicated subject. There are some reports of top ups with Group II to Group I's can make it real bad. I think we will end up trying a bypass filtration system with cellulose filter elements. There seems to be some evidence they can reduce the varnish potential in existing oils. This will be cheaper than replacing the oil, if it works. One other plant has reported good sucess with it. Here is a bit of information on one company that does this. http://www.klassenhydraulics.com/industries/pwrgen/CJC_GE%20GT%20Presentation.pdf
Ron more thoughts, In a on line OLD system using GPI with good bypass filtration (running at close to staturated "sludge" leval) I think over time or with a partial change to GPII the new oil will rasie the aniline point and knock out varnish and sludge. Otherwise as in a IC engine ANY oil run past its usefull life will varnish and sludge up. bruce So of a change is made to a "better" GPII oil the whole system should be chnaged out or a outside "filteration" company comes in a runs a full 100% cleaning of the whole system.