As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT WAS ORIGINALLY TO SUN VALLEY, BUT COULD NOT LAND DUE TO WEATHER. REROUTED TO TWIN FALLS. WHILE UNDERWAY, NR 1 OIL PRESSURE WENT TO 10 PSI, AS A PRECAUTIONARY THE NR 1 ENGINE WAS SHUT DOWN AND THE AIRCRAFT LANDED WITHOUT INCIDENT IN BOI. MAINTENANCE FOUND THE OIL COOLER LEAKING AND REMOVED AND REPLACED IT. AIRCRAFT WAS GROUND RUN, NO LEAKS NOTED.