Oil temp normal or gauge error?

[Scott Gaddini]

I've got a question about a possible oil temp indication error.  The Bonanza is new to me and have not flown a summer season yet but... the oil temp seems low to me.   I've attached a poor quality photo of the engine guages during a two hour flight in 60 degree air temp.  I've always been of the understanding that oil should at least reach 180 degrees during a flight and mine seems never to get close.  

I know the more oil in the tank could result in possible higher oil temps.  I tried putting in a few extra quarts which yeilded no temp rise and an hour of cleaning the belly. Ive tried 25/50xc, aeroshell 100W & 80 W, no differences.

Could the gauge be bad and need overhaul (which vendor for that?) ?

Could the connection or temp sensor be bad?

Or is this just normal?

[Lew Gage]

There are both electrical and Bourdon tube type oil temperature indicating systems installed on the E powered "real" Bonanzas. Which do you have??

A very simple way to check the operational accuarcy of thecockpit gauge is to obtain a long stem thermometer and after flying and engine shutdown insert the thermometer stem into the oil tank and compare the cockpit indicated temperature with the tank reading.

The oil temperature indicated on the cockpit gauge will be the same (for all practical purposes) as the oil tank temperature if the cockpit system is indicating correctly.

A suitable thermometer is available is from W.W. Grainger Co, their PN-1NFX or 1NGD9, 1% accuracy, 0-250F range, stem 12" long, both about $50.

I suppose that after doing the oil tank one could wipe off the stem and use it on the turkey next Thanksgiving.

Regards,  Lew Gage

[Lew Gage]

Oops, I left off the 9 on the first part number. It should be 1NFX9, not 1NFX. Again regards,  Lew Gage

[Doug Carr]

Hi Scott

are you running an electric or hydraulic prop?