Oil Pressure Guage really low

Might wish to mention which engine you have.

Someone else might be able to chime in here, but I believe there might be a difference where the oil pressure sender is located depending on whether or not there's an A/C pump mounted on the 2.8 engine.

If you don't have A/C on the engine where you can't find the sender, I believe it's on the passenger side/front of the engine (firewall side).

I know this is an old topic but I too have a low gauge
reading and red light flicker with a warm 1986 V6 SE. I
had it tested and the oil pressure is as spec'd for idle
and approx 2000rpm or so.   Forget what it was. But I was
told it was ok.   

Cheers

BTW - Just grabbed an AC Delco Filter PF52F from Lordco (like $5.00) and the holes in it are huge  compared to the equivalent Fram  I am hoping my oil flows even better now (til now was still using old school filter)

Curious - if the sum of all the small holes equals that of the large hole - is there a problem with flow/volume...?   Consider '9' small 1/4" dia. holes = 0.441 Sq. In.  then '1' large hole needs to be at least 3/4" dia. = 0.442 Sq. In. (all sizes are theoretical )  to equal volume allowable.   Has anyone ever measured the hole sizes for comparison...?

Romeo wrote: NEVER run Fram, unless you hate your engine and wish it a cold, miserable death.

See my previous post...a bit-o-science for ya.

Romeo wrote: Oil filters in generally will impede flow, but never to the point where they starve the engine. Again, if you look at what the manufacturers do, they focus exclusively on filtration, not flow. There's a reason for it.

You lost me.  I am still interested to know what it is that Fram does so wrong?

But I do like your statement "A single large hole will outflow numerous small holes due to oil's tendancy to cling to metal surfaces, but not other oil molecules." I so get what you are saying here.

kharmata wrote: Romeo wrote: Oil filters in generally will impede flow, but never to the point where they starve the engine. Again, if you look at what the manufacturers do, they focus exclusively on filtration, not flow. There's a reason for it. You lost me.  I am still interested to know what it is that Fram does so wrong? But I do like your statement "A single large hole will outflow numerous small holes due to oil's tendancy to cling to metal surfaces, but not other oil molecules." I so get what you are saying here.

David pretty much nailed the two major faults with what Fram used to do (Their lowest end still doesn't have an anti-drainback mind you). With an anti-drainback, when the key is turned off, gravity will pull the oil back down, back through the oil filter and return it to the sump. As David said, when the engine is turn over, there is a noticable amount of time while the oil works it's way back up to the pick-up, through the pump, over to the oil filter, through the oil filter and back up to the engine. And the bypass was corrected, but only recently. Tends to show you the quality level when the company would rather starve the engine than implement a part that costs a couple cents.

As for the other question, oil, by nature, sticks to metal; It slides against itself. If you look at a bearing, oil will stick to the bearing, and stick to the journal, but in between those two films the oil moves around freely, allowing the parts to spin with a minimal resistance. 5W-30, according to the Society of Automotive Engineers (SAE), will typically cling to metals by a thickness 0.001". Doesn't sound like much, but it does have an effect. A smaller hole means the ratio of surface-oil (0.001" all around) as compared to the area left for oil to move is less than that of a larger hole, where the 0.001" reduction means less. For example, if we look at my woefully crude MSPaint picture below, in the smaller holes, where black is the film of "stuck" oil, and grey is free oil, we can see that the smaller holes have more oil that doesn't move, versus the larger hole.