Mechanical oil pressure gauge

[Kevinstone]

Hello everyone, simple question here. I have installed a mechanical gauge with the plastic tubing. Should I be seeing oil in the tube,or air only? I see oil go almost to the top of tubing and stops about 6” from gauge

[Dave Neptune]

And you will see the oil go back down after shutting down. This is a sign of a good seal. I prefer using copper on mine as I have had the polytubing fail on a few occasions. The gage just "feels" the pressure and does not care what is pressuring it.

Dave Neptune

[Kevinstone]

Thanks Dave, I have copper tube also and will use that as my permanent install. Doing a test run today

[Al Schober]

I would NOT use the poly tubing. An alternative to the copper for a short run is an extension tube for a grease gun. This is high pressure tube with 1/8 NPT on both ends. Available at HD. If you're using it with the electrical sending unit, you need to run a ground wire to the sender.