The Ford Barn

gayle marlowe · 04-10-2021, 08:44 PM

Is there a way to test the oil pressure sending unit to see if it is the sender or the gauge?
Dash gauge does not show any pressure. I guess I could add a gauge under the hood but it is nice to have one where you can see it all the time.
Don't know if 6 volt electric gauge is available? Really don't want the typical round oil and temp gauges added to the under dash.
If it is the sender, great. Just replace.
If it is the dash gauge, will have to wait till next winter to tackle that.
But, would like to have something now to show pressure.

drolston · 04-10-2021, 10:24 PM

Watch the oil pressure needle as you turn the ignition switch on. It should move up from below zero a little bit. If the needle moves, the gauge is probably somewhat functional. If it does not move at all, take a volt meter to the terminal on the oil pressure gauge; it should read something close to 6 volts. If zero, check voltage to the power side of the gauge under the dash. It should have about 6 volts. Then check the other terminal of the gauge; if zero, the gauge is burned out. If there is voltage there but not at the sender unit, you have a broken wire or bad connector.

If the gauge is good, you need to remove the sender, and screw in a mechanical oil pressure gauge. If the mechanical gauge registers acceptable pressure (10 psi at idle) that comes up with rpm, then you need to replace the oil pressure sender unit. Get the 50 lb version for your '38.

Terry,OH · 04-11-2021, 07:31 AM

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Can test the sender using air hook up a battery and use the gauge. Older senders can become plugged with dry sludge from the engine oil. The sludge can be cleaned out without damage to the senders diaphragm.

04-10-2021, 08:44 PM	#1
gayle marlowe Member Join Date: Feb 2021 Location: pueblo colorado Posts: 40	oil pressure sender, 38 sedan Is there a way to test the oil pressure sending unit to see if it is the sender or the gauge? Dash gauge does not show any pressure. I guess I could add a gauge under the hood but it is nice to have one where you can see it all the time. Don't know if 6 volt electric gauge is available? Really don't want the typical round oil and temp gauges added to the under dash. If it is the sender, great. Just replace. If it is the dash gauge, will have to wait till next winter to tackle that. But, would like to have something now to show pressure.

04-10-2021, 10:24 PM	#2
drolston Senior Member Join Date: Jun 2014 Location: Williamsburg, VA Posts: 1,627	Re: oil pressure sender, 38 sedan Watch the oil pressure needle as you turn the ignition switch on. It should move up from below zero a little bit. If the needle moves, the gauge is probably somewhat functional. If it does not move at all, take a volt meter to the terminal on the oil pressure gauge; it should read something close to 6 volts. If zero, check voltage to the power side of the gauge under the dash. It should have about 6 volts. Then check the other terminal of the gauge; if zero, the gauge is burned out. If there is voltage there but not at the sender unit, you have a broken wire or bad connector. If the gauge is good, you need to remove the sender, and screw in a mechanical oil pressure gauge. If the mechanical gauge registers acceptable pressure (10 psi at idle) that comes up with rpm, then you need to replace the oil pressure sender unit. Get the 50 lb version for your '38.

04-11-2021, 07:31 AM	#3
Terry,OH Senior Member Join Date: May 2010 Posts: 4,743	Re: oil pressure sender, 38 sedan Sponsored Links (Register now to hide all advertisements) Can test the sender using air hook up a battery and use the gauge. Older senders can become plugged with dry sludge from the engine oil. The sludge can be cleaned out without damage to the senders diaphragm.