Mechanical oil pressure gauge help

[russcc]

Installed a SW mechanical oil pressure gauge from the NPF port at the back of the block on a 8RT to the dash. Do I need to bleed the air out of the line and gauge, or does it bleed itself on start up. If bleeding is required, need help with the correct method. Thank you, Fordbarners.

[roadster36]

I have never bled any of mine and don't know anyone that ever did. The amount of compressed air trapped in the line would be marginal as to how it affects the operation or accuracy of the gauge.

[40cpe]

Bleeding is not necessary. The gauge will read compressed air as well as pressurized oil. You will see spaces of oil and air along the transparent line but it won't affect the reading.

[Drbrown]

If your oil gauge indicator needle was fluctuating a little, this should stabilize it and you will not lose much oil in the process .... Where the oil flex line from the engine attaches to the back of the gauge, and holding a small can/jar under the connection, slightly loosen the fitting to let the oil drip out into the container from the gauge connection. If its a transparent flex line let the oil slowly drip out of the fitting until no air bubbles are seen. If the flex line is not transparent just let it drip or run until the oil slowly flows uniformly. If you change oil weight from one season to another, you may wish to take a few minutes to flush/change the oil in this feeder line to get the most accurate gauge reading.

[big job]

Over the years I actually learned to have air especially with a long run. Back
in the day working at a bus company, rear engine buses ran tubing all the
way to the dash. After time this tubing would get "oil logged" resulting in
being scarey with no gauge movement for 10 min. due to cold oil. So from
time to time we would blow out the line from front to back. Big difference
we then would get an instant reading. Having air is the same, call air over
hydraulics.....

[39portlander]

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Here is my set up that has a gauge on the engine side and below a sending unit for the one in the cab.

As stated above, no need to bleed.. Scott

[G.M.]

The only problem you may have is the gauge jumping up and down. This is due to a gauge that isn't dampened. Oil pressure gauges need a small restriction hole the avoid this. They are sold and sometimes called snubbers. G.M.

[Old Henry]

Never bled mine. Works just fine. As has been said, the gauge reads the pressure whether transmitted by compressed oil or air.

[Johnnydidd]

At idle what should the oil pressure be, mine is 10 lbs hot, cold around 40 lbs. I have both dash gauge, under the dash and one under hood. The under the dash and under the hood read the same.

[G.M.]

Originally Posted by johnnydidd

at idle what should the oil pressure be, mine is 10 lbs hot, cold around 40 lbs. I have both dash gauge, under the dash and one under hood. The under the dash and under the hood read the same.

perfect. G.m.

[39portlander]

Originally Posted by G.M.

The only problem you may have is the gauge jumping up and down. This is due to a gauge that isn't dampened. Oil pressure gauges need a small restriction hole the avoid this. They are sold and sometimes called snubbers. G.M.

Being in the HVAC world we use liquid filled gauges, a little more $ but keeps a steady needle. Scott

[G.M.]

I have a liquid pressure gauge on the fuel line of my Duramax diesel it is nice and stable. Most cheap pressure gauges have a small damper hole but I have ran across a few that were not. I put about an 8/32 thread in the input hole, drilled about a .025 hole in an 8/32 screw and screwed that in the gauge. Grainger and McMaster Carr sell "snubbers" that screw on the end of the gauge. G.M.