'48 truck oil pressure gauge

[1948F-1Pickup]

I originally replaced the sender with a NOS one (41A-9278), thinking that my factory gauge reading would be fixed........ it always read no more than right around 30. The mechanical gauge reading would be anywhere from 20 to 40 and the electric one would be around 30 and usually within 1/8" of the 30.
(pretty much the same exact behavior I had with the factory electric gauge
before getting the NOS sender)

New engine now. Mechanical gauge max is right around 60 warming up and
about 45 hot and motoring around town.
And as you might guess, the electric gauge in the dash........ still reads right around the 30.

Makes no sense. Could the factory electric gauge be bad? And having a bad electric gauge doesn't really make sense either.....

[TJ]

Did you use anything like teflon tape when installing the sender? If so you don't have a good ground for the sender and affects the gauge reading..

[1948F-1Pickup]

I always use a very light bit of permatex white teflon sealant on the senders but I'll do a temporary ground to the sender's case tomorrow to rule out that possibility.
Thanks for that.

[Ross F-1]

The gauges can be adjusted, and they seem to "age" towards lower readings. It needs to be done slowly and carefully. FWIW, my dash gauge has always read about the same as yours, and a mechanical gauge shows about the same as yours.

[1948F-1Pickup]

Thanks for that info, Ross.
I'll look into that as well.

[1948F-1Pickup]

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Temporary additional ground at the sender yielded no change at the gauge, so that's ruled out.

I did find a Barn thread on the subject of the oil pressure gauge in question.... reading that right now.

https://www.fordbarn.com/forum/showt...4760&showall=1