Oil pressure as a rpm Guage?

[Youngbuck7072]

so it really wierd, when i start my truck, the oil pressure gauge is about halfway, and then when i rev it up , the needle is PINNED the the right to the point that you can barely see it anymore. WHat the hell is this???!!!!

[jayman68]

Possibly the pressure regulator in your oil pump has failed. The oil pump has the ability to produce a couple hundred p.s.i.

[78bronzechariot]

Has it always done this, or is it a recent occurrence? My '78 Caprice that I built a 375 horse 350 for has a high volume pump and hits 75 psi on a cold start, and runs about 55-60 at 2000 rpms warmed up. I wouldn't be surprised if a PO put in a high volume pump to boost weak oil pressure or because that is what the parts store had. Other possibilities are more simple like the capillary tube is/was clogged or that higher than normal pressure has damaged the gauge at some point.

[Blazer1970]

That is totally normal. Oil pressure will always be lower at idle and rise with engine RPM. The dash gauge is only 60 psi, so a good tight motor with good oil pressure will pin it at higher RPM when cold. Does it run lower on the gauge when the truck is warmed up?

[Youngbuck7072]

well its a brand new motor, and the guages came from another truck, so...?

[ChevLoRay]

So, you can understand my concern when one of our bus engines is sitting at almost zero-lbs of oil pressure when it is hot. We have high-volume, low-pressure pumps in them, but I still get antsy when it drops so low.

If you have any issues like that, which aren't due to such an oil pump Power-Up is a good additive. It protects at low pressures. We've run it for years and also used it in gearboxes and trunnions that are subject to high heat in an industrial environment. But it works well in school bus diesels.