Posted by Jake on August 30, 03 at 08:14:42:
In Reply to: Oil pressure posted by Bryan on August 29, 03 at 19:38:33:
Bryan,
There are a lot of variables at work here. First of all, I would not base any diagnosis on the dash gauge. Remove the oil pressure sensor and connect a quality mechanical oil pressure gauge to use during troubleshooting.
But, based on what you've said here's what I think. Oil pressure will vary with rpm. The older the engine, the most this is prevalent. For a 98, you should probably have close to 100K it by now. The GM specification for oil pressure is 10 psi for each 1,000 rpm. You seem to meet this easily, so I don't think your engine is going to suffer any damage from low oil pressure. It is common to see the oil pressure increase with rpms. This is also temperature dependent. In hot weather at idle, expect lower pressures. On a cold start-up you may see much higher pressure. My truck will idle at about 35 psi and then hit 55 psi as soon as it comes off idle. Cold start-up pressure does go as high as 75 psi. I did replace my oil pump at 110K. I have a total of 165K on the rig now. The dealer was fixing an oil pan leak, so I had them put in a new pump. All I paid for was the pump. Installation was FREE!!! It was easy since they already had the pan off. I had noticed a slightly lower overall pressure (lower at idle and lower at speed). The new pump restored oil pressure to "like-new" condition. As I plan on keeping this one for at least another 150K, it was a wise investment.
Erratic oil pressure readings could be the sensor. Replacing the sensor is cheap and easy. I would recommend it in this case. See if anything changes.
Good luck,
Jake
96 K2500 6.5TD