For the uninitiated, an oil temperature probe is required keep a check on the oil temperature. The oil temperature is vital to maintain its viscosity. A low temperature will make the oil useless whereas a higher than normal temperature will risk a whole lot more than just engine damage.
An oil temperature sensor is inserted into the aircraft engine (please see latter part of this article on how to install the oil temperature probe), and the wires are connected to the oil temperature indicator or EDM if your aircraft cockpit sports an EDM. If the EDM permits it, the pilot can pre-set an alarm for the oil temperature so an audio-visual alarm sounds if the temperature drops to below a certain level or raises above a certain level (usually 180F or thereabouts).
Since oil plays a vital role in any aircraft, the pilots need to ensure the oil temperature probe and gauge are not only in good working condition, they are also accurate. This is done by an expert mechanic who will spot oil temp probe / gauge calibration errors. All such errors need instant attention – either recalibration or a replacement.
Once the mechanic completes his task, it is best if the gauge, sensor, and interconnect wiring be calibrated by a qualified technician or agency before flight. This is deemed prudent as even a small 5% or 10% make a huge difference to the engine. The error could result in the pilot take unnecessary measures or not taking any measures. The latter especially could prove fatal. From experience, we can state that even new oil temperature probes need calibration – or at least testing to ensure the reading they provide is accurate.
These days however, with the arrival of IC based integrated avionics and LCD displays, engine data is generally more reliable than what they once were just a few years back.
J.P.I. manufactured EDM’s allow for the display of several different engine gauges on a small but clear to read LCD screen.
Installation of the oil temperature probe in aircraft
The Oil Temp Probes in aircraft is installed by removing the pipe plug located on the front of the engine inline with the push rods. This oil galley feeds the valve lifters. Insert the probe supplied with the kit and check for leaks after installation. The probe leads are routed back to the cockpit along with the EGT wires. Attach these to the appropriate gauge or EDM.
More information on oil temperature probes can be found here: https://www.jpinstruments.com/shop/oil-temp-probe/