Rochester oil temperature gauges adapter nuts.
5/8-18UNF x 5/8-18 UNF.
Arrived quickly! Off and running again!
This adapter nut has the correct conical seat inside for the Rochester temp gauge instead of the flat seat required for the former Scott temp gauge which the Rochester is supposed to be a replacement for. There was a service bulletin issued at one time for the change in the gauge probe and the requirements for the adapter nut. The requirement for the conical seat was not mentioned in the catalog neither was the requirement for a gasket between this nut and the engine receptical that it screws into. I found that an AN900-10 or an MS35769-11 annular copper=asbestos gasket fits this requirement and fortunately I had one.
The hole in this adapter is too small for the vintage temp sensors I have. Seems that it might only fit the Rochester bulbs. Use the other adapter spruce has listed. It is brass and fits everything.
Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.
One side is .375" and the other is .580".