HighPro

OK, I know this is an old subject, so, don't beat me up too much. I have an 09 Z06 and when it is warm it idles around 550 rpm. The oil pressure 5-30 Mobil 1, is at 40 pounds at warm idle and at about 50 at a warm 55 mph. I checked the oil by letting it sit for about 5 minutes and it seems about 1/2 or less of a quart low. What are your readings and do I have a reason for concern?

50 4Ever

Your oil pressures seem about right. I can't say about the idle because I have a cam and it idles about 750.

As long as the oil temp is up to normal operating temperature you're checking it correctly. Oil level anywhere in the hatchmarked area is fine except when doing aHPDE - in that situation the oil should be a the top line.

JoesC5

mine idles at 600 RPm and the oil pressure depends on the oil temp. Your's sounds okay. A half qt low really depends on where it was at the last oil change and how many miles it's been since the oil change.

JJC5

Mine runs at 60psi at 65 to 70 mph (forgot the RPM at that speed) in 6th gear consistently while at normal temps. Idle is 45 at normal operating temp and 60 when cold. My oil level has stayed at halfway between the top hole and middle hole which would be 1 pint lower than full.

HighPro

Thanks Guy's!!! This forum is GREAT. I had concerns because it seemed low - for some weird *** reason. You guy's put my mind at ease.

Appreciate it,

Erwin

AzDave47

My 09 with oil temp at 260* (HPDE) will idle at 20PSI but be 50-60PSI in the higher RPM range. The owners manual says that is normal. Under normal temps mine is similar to your PSI #'s.

On oil level at 175*, 5 min after shutdown, mine is at one hole down from the top. Then at 260* 5 min after shutdown it is at the top mark so the extra heat moves it one mark higher.

With the 09's and newer with the 10 1/2Qt tank and the expansion I see with hot oil, I want it to be one mark down at 175*

jester139

I just took my 12 GS manual with dry sump in to the dealer due to oil pressure pegging at 80 PSI when over 4k RPM.

They said bring it in, but when I did they stated it was normal due to dry sump package. They also stated they checked it against Z06. I switched to the digital readout and saw a peak at 117PSI. They claim it will shut down if it gets too high, but don't want to get to that point.

Anyone else seeing this?? It does not seem right to me.

jedblanks

117??

Random84

The oil level in your reserve tank has essentially nothing to do with oil pressure (unless you are REALLY low and the pump is running dry - obviously not the case here).

Oil temps definitely vary by temperature and oil weight, and to some extent can vary by car due to variations in engine and pump tolerances. So if you're running the standard Mobil 5w30, and by "warm" you mean your temps are 200* or more, then your oil pressure is perfect. But if you change the type of oil used, or if the oil temps are hotter or colder, you may notice different pressures at different temperatures.

For the vast majority of drivers, subtle variations are not significant and changing the weight of oil is not desirable. As long as you HAVE oil pressure, you're usually in good shape.

ByByBMW

GOLD72

My 06Z would routinely idle at 28-30 psi with normal oil operating temps from freeway driving. My 2011 ZR1 runs about the same as well. There is nothing to be concerned about.

jester139

Yes 117 PSI. I called two dealerships and neither has a spec for high oil pressure.

MitchAlsup

The standard rule of thumb is that you need 10 PSI for every 1000 RPMs. So with 40 PSI at 600 RPMs you have plenty of pressure.

It is not pressure that lubricates an engine, it is pressure that refills the journal bearings after a load-event has thrown oil out of the bearing. The pressure of the oil pump does NOT do the "prevent metal to metal contact" thing. It is the viscosity of the oil that does this job.

Also note: viscosity is measures in Stokes or Poise whereas oil is sold in weight grades. A weight grade has a window of acceptable viscosities at a low temperature and a second window of acceptable viscosities at a higher temperature. SAE defines the low temperature to be 40dF and the high temperature to be 212dF.

The standard rule of thum needs to apply durring the entire life of the engine. So an old worn out engine still has adequate oil pressure after the journal bearings have significantly larger clearances and the oil is thrown off with much greater ease. So new engines are tight and the oil pressure will be correspondingly higher.

Oil pressure does not have to be, need to be, or is it even desired to be constant over the whole RPM band. Many new engines essentially operate constantly at the pop-off pressure in the oil pump, There is a spring oaded valve that opens when the pressure gets too great. This prevents seals from bursting, pipes from bursting, and other engine anomolies. The pop-off pressure of the LS engiens is in the range of 60 PSI. When you are operating at the pop-off pressure some the energy your engine spent pumping the oil up to that pressure is completely wasted.

Oil does some amazing things on its way through a journal bearing. First it keeps as much as 50K PSI from making metal to metal contact, and by doing this it can increase in temperature by 20dF in the few microseconds it performs the load bearing feet. The oil is, in effect, taking the heat out of the 'pressure times distance' part of work and energy being transmitted through an engine.

JJC5

Nice write up!! Interesting information there.