Oil pressure

[patrickt]

Originally Posted by Blackbart

Is it necessary to "bleed" the oil line from the oil filter (FE Engine) to the oil pressure gauge to remove air trapped in the line? It would seem to me that oil and air compress at different levels and if there is air in the line the gauge may not read true oil pressure.

No, the gauge will work just fine.

[bobcowan]

In theory, you are correct. With air in the line it will not be exact. But the difference is so small that it won't matter.

You can use a syringe to inject oil into the line befor connecting it too the gauge if you want to. But eventually most of the air will purge itself.

[cycleguy55]

Fluid compressing air will result in the same pressure reading - or close enough to not matter.

[eschaider]

+1^ on what Brian said.

If the oil is at 50 psi, for example, it will compress the air to the same 50 psi. The volumes will be different because the oil is essentially non compressible and the air is not. The volume differences not withstanding the pressures measured in either the oil or the air will be identical.


Ed

[patrickt]

Damn, you all must have nothing to do today.

[Gaz64]

Originally Posted by eschaider

+1^ on what Brian said.

If the oil is at 50 psi, for example, it will compress the air to the same 50 psi. The volumes will be different because the oil is essentially non compressible and the air is not. The volume differences not withstanding the pressures measured in either the oil or the air will be identical.


Ed

That's also why you can use any pressure gauge to measure any type of pressure, as long as the scale is appropriate. Eg: fuel pressure gauge for boost pressure.

[CoyoteCobra]

misread post