Mine is a 93 4banger and when we replaced the sending unit it had ruptured and was leaking oil all over the side of the block.
It was that way when we bought it. That took some time to track down as the oil PSI gauge stood at zero. We did have to
buy a special deep well socket with a notch to remove and reinstall the sending unit. Replaced with an aftermarket unit that worked about 3 months, now idels at 40 psi and pegs at speed. Local 4WD shop suggested replacing with oem unit. Thats on the to do list, BUT Ill check the actual oil PSI with a test gauge just to be sure of actual PSI at idle and reved.
Hope this helps