95 Aurora Oil Pressure Readings

[MarkWilliams64]

What are the correct oil pressure range for an 95 Aurora 4.0L.
When engine is cold and started, idle is about 30psi and at 50Mph about 55psi.

Once the engine is warm idle pressure is 8-10 psi and 40-45 at 50 MPH.

The idle pressure seems low to me at idle once it is warm.

These pressure readings are from the digital readout on the dash.

Engine has 85,000 miles on it.

[maxwedge]

I would give this advice to anyone one asking this question on any car, I assume you have fresh oil at the right weight, if so get a mechanical gage on the oil pressure port and see what it reads, could be a bad sender.

[MarkWilliams64]

Thanks maxwedge, hadn't thought of that will do.

I am assuming the oil pressure port is on the block someplace, which getting to on an Aurora may be fun. Man that thing is packed in there.

Anyone who knows the exact location of the port, so I don't have to go on an exploration. The help would be appreciated.

Man I hope it is the sensor cause the engine seems to run pretty good for the age.

[peeweewasblue]

The oil pressure sending unit is on the adater that holds the oil filter. So for a change on an aurora, it is not hard to get too.

[MarkWilliams64]

Thanks peeweewasblue, I will check it out tonight after work.

[MarkWilliams64]

Mechanical Gage installed in the Port as suggested.
Plenty of oil pressure at start up, 45 - 50 psi.
After running for a few minutes, down to about 30 psi at idle.

After running for several minutes, Engine temperature around 220, little to no pressure on gage at idle. Idle is about 700-800 rpm.

When engine is held at 3000 rpm have about 45 psi.
At 2000 rpm about 35 psi.

The oil has less than 1000 miles 5W30.
However the Engine was not run for about 10 months.

Thinking about changing the oil and filter maybe 10W30 or 15W40.

Let's hear your thoughts guys.

[MarkWilliams64]

Seen a couple of older posts on here about, switching to a higher grade viscosity and or full synthetic to fix the same problem.

That will be my next attempt.

Also found an interesting post if you have no oil pressure all the time.
It references a TSB that says to add 10 to 12 quarts (Extreme Over Fill) to flush out a pressure relief valve in the pump. But that is for if you have 0 oil pressure all the time, not if it falls to extremely low pressure at idle, but you have adequte pressure at rpm. Very interesting though.

[maxwedge]

Not sure what the specs are for the " baby N'star, but it sounds low, This is not good as heavier oil is not the answer. Internal bearing clearances are the usual issue assuming the pump is not just worn, as mentioned I would do some tsb research on this issue for some advice.

[MarkWilliams64]

The 10X30 Synthetic Blend helped, but as maxwedge says probably not the fix.
But at least the pressure doesn't drop as far.