Oil Pressure Problem!!!

[Chevyguy]

Low oil pressure means excessive clearence between the bearings and crank. When the motor heats up the clearence expands and the oil viscosity drops. This is not a good thing.

As for the gauge, there is a diaphram and a spring, the oil pressure forces the diaphram back this gives the voltage reading which is converted to PSI (sort of) The sender unit can get crapped up internally and give erratic readings.

Bouncing readings sound like a crappy sender to me, get a new one on there first.

The stock gauge is pretty good actually, most dont want to face the fact the engine needs a rebuild!!

My car reads 70 - 75 PSI cold. 50-55 psi while driving hot, 10- 20 psi at idle ( Very bottom of N) so I know the bearings are getting kinda thin at 150,000 miles.

My beat up 305 in my Chevy has a reground crank and new bearings and oil pump. Even when fully hot still gets over 40 psi idling in drive.