GM-GMC: Oil Pressure 5.7 Chevy, chevy blazer, pressure relief valve

Question
Hello
The oil pressure in my 1994 Chevy Blazer has been getting lower each year. I have replaced the sending unit, and have changed the oil faithfully. I have been told that their is a spring internally that controls the flow of oil and that their might be some dirt in the spring causing it to alter the pressure. the motor only has 58,000 miles on it. Question is this true-? and how and where do you change such a spring.
What would be your thoughts if this is not the case.
Thank You
R

Answer
In modern engines, not much dirt or contamination gets into the oil system.

There is a pressure relief valve in the oil pump and a bypass valve for the oil filter.  It is not likely that either one is causing your problem.

All engines wear, and some more than others.  As bearing clearances increase, resistance to flow decreases.  This causes a lower oil pressure reading.

If your engine is not making strange noises and runs properly, I would just keep driving it.

Your gauge may also be inaccurate.  A mechanical gauge should be installed to confirm the reading that your electrical gauge is providing.