@Lonewolf_50: I don't know the 225, but I don't know of any helicopter with an indicating system that senses oil return flow (or oil supply flow for that matter, whether that be in an engine or gearbox).
Oil temperature, where a thermocouple is inserted into an oil flow line or sump somewhere, obviously requires oil to be in the system for the probe to measure the oil temperature. If oil system volume is decreasing you should see an increase in temperature as the available oil is spending less time cooling down before it's heated up again. But you need to be looking at the gauge, I don't think there is an oil high temp warning on a CWP?
And oil supply pressure, usually on the output of the integral oil pump/s built into or on the gearbox (or engine). Oil pressure should be dual function, low pressure switch and pressure transmitter. Without oil you might not see a high temperature indication, but you should see a low oil pressure indication, and a low oil pressure warning on the CWP.
If there is an anomaly in the oil flow circuit somewhere (such as a blocked oil jet), you might only get a slight increase in the oil temperature indication, but still within the normal range.
I guess most people here know all this anyway.