Noticed after a spirited drive yesterday that the oil light in the combo gauges was flickering at a stop light. Car idles a bit low, but have not seen that happen before and clearly not a good thing.

Light immediately goes out once the RPMs go over 1000 and stays out.

Engine has good power, doesn’t smoke, and is generally an enthusiastic performer.

Any thoughts before I assume it is rebuild time?

Thanks in advance for the help.

I would put an oil pressure gauge on it to see the pressure at higher revs before assuming you need a rebuild.

Idiot light sender has always been sensitive to pressure variance at low RPM. The oil pump is a positive displacement gear pump. Output is directly proportional to RPMs. 10 psi per 1000 RPMs is the generalization for acceptable oil pressure but down an the low end near idle you won't necessarily get that.

However, if your RPM's are dipping down at 800-850 rpm you will end up very near the threshold of the idiot light sensor with some wear in bearings, oil pump condition, etc. From the Haynes manual the oil pressure switch is set to come on between 2- 6 psi but there is a lot of variance in that spec and I'm sure some sensors are probably more like 7-8 psi with production variation.

Make sure vehicle idles at least 900 RPM but better to put it toward the high end spec of 950.

Thanks for the detailed response.

My idle is closer to 750, I'll look into adjusting that.

Fresh 20/50 oil BTW to proper level.

Am I correct in thinking that getting to the oil pump (which won't fix worn bearing off course) is a split the case job?

No it is not a split the case job but it is a remove engine, remove fan shroud job.

But . . . you're thinking about this in the wrong way. If you don't have proper pressure, replacing the oil pump isn't the solution.

Oil pumps rarely "wear out". They do get scored from pumping junk. But if they are pumping junk, you have to ask where is that coming from? You won't like that answer.

Bump RPMs and measure with gauge before jumping to catastrophic conclusions.

Hey now - don’t deprive me of a proper freak out moment by providing actual data or facts.

Agree that replacing the oil pump won’t change a bearings issue.

Dino oil? I have found that cooking dino can lead to lower pressures and any oil is going to be incredibly thinner at high temp. Combine that with an idle that is far too low I bet many of us would get oil lights flickering.

On my car I see almost a 8 lb decrease at idle hot oil versus not as hot. As I drive safely around town and the oil temp comes down I get all 8 lbs back. The car sits at 10-12 ish hot hot idle and 18-20ish when not burning hot. That is at 900-950, not 750.

I assume you checked your oil level again? Even the owners manual says burning a quart in 500-1000 miles is normal (!). You might just be a little low after that spirited driving. Low oil will also result in hotter oil and therefore thinner oil.

Good morning, after checking the oil level again this morning it did need to be topped up a touch. Will bump up the idle speed some.

Going to watch everything carefully and just drive and see what where that get me (so to speak).

Thanks!

I wish it were easier for people to put oil pressure senders on these since knowing the actual pressure is pretty nice. Sadly, unless you get the perfectly right fitting for the block it's a pita.

And truthfully, if your bearings are going, no amount of knowledge will save you, but you could reduce the damage elsewhere if you saw a dropping pressure over time. A smart move, and a way to make yourself feel better, is cut the oil filter apart and look for sparkles. Same with the oil. No sparkles, all good.