The Cessna 120-140 Association Forum

Installed new mechanical oil temp gauge and didn't work at first. Found that if I backed off the nut that tightens the probe in place the gauge works fine, but I get a very small oil leak. If I tighten the nut so the fitting doesn't leak, the gauge doesn't work. Looking for any ideas. Wire from gauge to probe is not kinked or any problems that can be seen.

That soesn't make sense to me. However, I know of at least 3 different adapters, and they cannot be interchanged. (See Neal Wright article on the subject). Did you use the adapter that came with the new gauge?

Yes, I used the adaptor that came with the gauge. It is identical to the old one I removed. The only thing I can think of is if the probe is touching the oil screen, if that could prevent the gauge from working

8180 wrote: ↑Sun Aug 19, 2018 6:50 pmThe only thing I can think of is if the probe is touching the oil screen, if that could prevent the gauge from working

I can'tt think of anything tightening it could do that would prevent it from working. The bulb and tube are filled with a gas. When it heats up the gas expands and moves the needle. (It's a pressure gauge underneath it all.) Cut off the pressure and it stops working...