Welcome to the CPL AGK question and answer forum. Please feel free to post your questions but more importantly also suggest answers for your forum colleagues. Bob himself or one of the other tutors will get to your question as soon as we can.
Imagine my 'delight' when, only hours after reading the section on oil systems in Bob's book on CPL General Knowledge, I was in an aircraft experiencing a problem with the oil system. .. !
This one stumped me, however. The oil pressure was steady, and in the middle of the green arc. The temperature needle was mostly reading 'zero' (sitting on the post at the bottom of the gauge) and occasionally jumping up suddenly to the middle of the green arc, then falling back down again.
It hasn't come back from the mechanic yet.
The only explanation I can think of is a fault in the temperature sensor or gauge display.
(Well-maintained Cessna 172R, 6.5 quarts of oil, problem emerged after a 2 hour flight, 2 hour lunch interval, 0.5 hour into the next flight).
This got me thinking - pilots should check the T and P regularly, but if a reading is anomalous, is there a standard set of rules for interpreting it - a sort of cheat sheet or quick reference guide for different anomalous readings? Clearly if the pressure had left the green, or if the temperature had been consistently high or low (and believable), we would have done a precautionary or emergency landing regardless of the interpretation.