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39LZ oil pressure sensor

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Two questions;

1. small consistent drip from oil pressure sensors.  Is it just a matter of tightening the fitting; some something more, gasket, etc?

2. at cold start, oil pressure goes to 50 pounds and stays there, even if I drive it 30 miles.  Sensor in engine, gauge?

step by step on how to test each,



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You can test the sender by applying air pressure to it, but I think that it is working correctly, it is just the incorrect sensor for your car. You can install a mechanical oil pressure gauge with a "T" fitting to check out the sending unit and then you will know your oil pressure.


There are two different oil pumps for the Zephyr, a 50# one and an 80# one. Your description of the problem sound like what happens when an 80# pump is installed and the sending unit is 50#. The sending unit must match the oil pump pressure. The gauge reads 50# max, so with an 80# pump and sending unit, full scale is 80# and midpoint is 40#.




If your unit looks like the one in the link, it will have a number (50 or 80) engraved on one of the flats of the square brass part. If there is no number on the square part, it will be a 50# unit. If the sender does not look like the one in the link, it is an incorrect type and should be changed.


The leak can be because the wrong sensor is installed. The correct sensor has pipe threads and tightening should stop the leak. There are sending units that look and work just like the original King-Seeley unit, but have fine threads.


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the 39 LZ had an electric oil pressure sense, right?

I thought King-Seeley units all were bourbon bulb and tube, ?

so if it is an 80# pump, and I change to an 80# sender, do I need to replace the gauge on the dash to read 80# max?

I'll get under car this week to look more closely at sender.

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King -Seeley made both types of gauges. I have an 80# pump and sending unit in my 40 Mercury with the original 50# gauge.  I don't need to know the actual oil pressure, just that there is enough pressure and that it does not drop on acceleration. When I do need to know the pressure, I can adjust the reading to an 80# reading.

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