Hello everyone! I posted this question on another forum but it doesn't seem they are very active so I'd like to give it a shot here.

My first question to my fellow Montero appreciators is in regard to the oil pressure sending unit. The original one was kind of erratic, so the check oil lamp would come on sometimes. After reading many posts here and other forums/the internet it seemed the general consensus was to change it. I got the one for the gauge (as mine is a 1990 LS) and replaced it. I should tell you that when under the car in the limited space, I got a little disoriented so I initially tightened it a bit by accident. Rookie move. Got it off and the new one didnÔÇÖt want to go on at first. Had to find someone w/ a tap to neaten the threads a little. It finally went in and all seemed well. At night, though, I noticed the oil lamp was still glowing, very faintly. I took my car to a neighbor mechanic and had him check the oil pressure using a gauge. At idle it read around 15 psi, I think. Normal based on the readings others generally get (based on what I've read online). He put the sending unit back on and IÔÇÖve been driving it since, and during the day I canÔÇÖt see any light, but at night, itÔÇÖs always there. It sometimes gets slightly brighter, but never fully lit, itÔÇÖs on when the running lights are off. My oil pressure gauge usually reads about 30 psi (or just less), about 15-20 psi idling, and once on a long trip on a warm day it was a little lower (oil heated up?). Anyway, I changed it out about a month or two ago, and it has been the same ever since. Any thoughts?? (Also, I use Pennzoil High Mileage 10W-30, which I've seen recommended online for this rig, but my mechanic just told me it's the worst oil out there...)

This is the one I got, for gauge:
https://shop.advanceautoparts.com/p...h-s933/5972191-P?searchTerm=Oil+pressure