Here's a conundrum - Commissioned 2000, 912 ULS 750+ hrs, Third Owner (done most of the hours). Another thread prompted me to check out my Radiator Cap next time I had my cowl off (today). Cooling system has always worked very well. No complaints. All required rubber (hoses etc) replacement done on time. Existing radiator cap 0.9 BAR (13 psi) - possibly never changed (certainly not by me). Cap appears to be in good functioning condition. Rotax manual (and other thread referred to above) recommend replacement cap 1.2 BAR (17.4 psi). I have the new cap but if I fit it, the internal /operating pressure of my cooling system will increase by 0.3 BAR (4.4 psi). I fear the increased pressure in my now quite old system. What would you do??