What was found
R ENG OIL QUANTITY WENT TO 0 BY TOP OF CLIMB. PRESS WAS 180 INITIALLY. APPROXIMATELY 10 MINUTES LATER OIL PRESSURE BEGAN TO DECREASE, EVENTUALLY BEGAN TO FLUCTUATE SO WE DECLARED AN EMERGENCY AND DIVERTED TO MCI. OIL PRESSURE FURTHER DECREASED TO 90 PSI WITH FLUCTUATIONS SO WE LEFT R ENGINE AT IDLE. 3-4 MILE FINAL OCCASIONAL PRESSURE FLUCTUATIONS TO RED BAND. I DIRECTED THAT WE WOULD LEAVE THE ENGINE RUNNING AND SHUT IT DOWN AFTER LANDING. ***EMERGENCY DECLARED*** REMOVED AND REPLACED DEOILER HOUSING O-RING IAW AMM 72-61-10-4. RAN ENGINES AT IDLE FOR 5 MINUTES AND HIGH POWER FOR 5 MIN IAW JRH. NO LEAKS OR DEFECTS NOTED. A/C OK FOR SERVICE.