I installed two of the Harbor Freight window vent openers and they have gone bad, both will not open. I have take one of them apart understand how they work. What I need to know is what type of oil is used in the cylinders to make them operate I have tried several different oils (mineral oil, pneumatic oil, vegatable cooking oil) but the temperature requierd to make work is to high. The vegatable cooking oil takes about 150 degree F. Does anyone know the type oil used. The o-ring seal are avilable at local hardware and like wrote vegatable works but the temperature is wrong