I have an LO3 with over 186k miles on it. The engine runs VERY good, nearly flawless. However, the oil pressure lately has been lower than normal. At WOT and RPM's in the 4-5k range, the pressure is just barely over 30. However, when the engine is warm and running at idle, sometimes the needle drops down just below 15 or so (the first line) and the pressure would never get that low until about a month ago. As soon as I hit the gas and the RPM's rise the pressure obviously rises as it should, but the low pressure at idle makes me worry a little. Is this normal, or should I be concerned?

 

could be the bearings getting a bit sloppy...


The best thing to do is stick a mechanical gauge on there for a minute, it could just be a screwy sending unit or gauge!

 

Verify with a mechanical gauge or try replacing the sender.

 

Time for gear lube.

 

I have had the same exact problem with several om my gauges, especially the oil pressure gauge. The circuit board on the back of the gauge cluster is made from a very thin flexible plastic. I took out my gauge cluster and brought to a friend's house. He is an electrical engineer and designs circuit boards for his company. He inspected the circuit board with special scope he uses in his business, he found numerous microscopic partial cracks in the filaments and explained to me that the material used was TOO flexible and over time just road and operating vibrations caused the cracks, and causes the misreading of the gauges. My water temp gauge always shows my car running hot, my friend has a laser temp device and he took readings all around my engine and radiator and my car was running 40 degress cooler then the gauge showed.