another mechanical oil pressure question

[9073]

I recently installed a mechanical oil pressure on my 1990 f-250 idi. and have a couple questions

the guage reads a little over 25 psi at idle (50 psi cold idle) when you turn the vehicle off the guage doesnt drop that much below 25

is this normal or is the guauge faulty?

the new sending unit for the factory oil pressure guage reads always in the mid normal range

Thanks

Matt

 

[160k87F250]

A mechanical guage should read correctly when the truck is off or on. When off, it should read 0. That what mine does. My temp also reads no matter if the truck is on or not. Sounds like you have a defective mechanical oil pressure guage,
John

 

[Mr_Roboto]

If its a true mechanical guage (with a capilary tube) it should read zero with the engine off. Sounds like you have an issue. It doesn't do you any good if it never goes under 25 psi. You'd never know if you lost pressure.

Your factory guage will always read in the middle whenever it has 5+ psi. It is an idiot light made to resemble a gauge. Don't believe me? Short the sender lead directly to ground. A true gauge would go to full peg. Your guage will only go to the "normal" spot.

 

[deanj]

If you have no oil pressure the guage should read "0" eg the engine is not running. Not running - no pressure in the tube - "0" on the guage. Running - oil pressure in the tube - reading at the guage. You have a defective guage. As for the temp, if it is mech it will read with or without the engine running, it is just a bi-metal strip sending a signal to the guage.