Shame on me, I need to clarify the clarification. . . Obviously, motor oil is a liquid (at least we hope it stays liquid), and thus, is a non-compressible fluid. So I should have said, "The pressure increase you typically see with increased rpm is NOT from the oil flowing "faster," it's from the pump attempting to introduce a greater volume. . ." That's a still-sloppy way of saying that the pump is exerting greater pressure on the input side of the oil circuit.

 

I just noticed when my car is cold (just started after its sat for a while) and I go WOT it goes to about 110-115 psi. But when its warmed up it goes to 90-100psi.

When I was using mobil 1 it would always goto 120psi. It could be more but it doesnt read more.

So you are right oil pressure is related to the pump and not the rpms. So I would say your pump is working hard at 120. So I guess that could be bad?

 

I noticed the same thing. When my motor is cold in the morning if I rev high I read 120psi or above on the meter (I dont do this anymore I just cruise at 3k rpms till it gets warm). Later in the day WOT gives me about 90-100 psi. Still seems high so I think I may switch to a lower viscosity oil ( 0w-30?). It never goes below 50 degrees in FL so that should be fine right?

 

Don't be thrown off as to viscosity by the "0w" part of the rating. The "hot" temp rating, the second of the two numbers, is what you should look at primarily, in most cases. Viscosity is defined in ranges, not as absolute values. The units that seem to be most frequently used are "centistokes," a measure of a fluid's "thickness" or resistance to flow. The Mobil-1 30 wt oils are all fairly "thin" 30s, rated right around 10 cSt, actually making them darned near being 20 wt oils (the 30 wt range is 9.3-12.49 cSt). This includes the 0w-30, the 5w- and the 10w- as well. In other words, when they're hot, they're all very similar. The 0w-30 German-made Castrol Syntec that I'm using (the non-Group-III stuff) is actually a very thick 30, measuring over 12 cSt when hot. In short, don't look to the first number to characterize an oil as thick or thin.

Before I got too concerned about the oil pressure figures, or concerned enough to change oils, I'd find out what the specs are for the normal range of oil pressure. On top of that, I'm not too sure you can count on the guage being precisely calibrated either, but that's another story. If your engine is behaving normally, check these things before taking more drastic action.

 

does anyone know what the "normal range" is for the oil pressure?

 

I think someone said it is 57psi at 6000rpms. I'm sure it could be found in the owner's manual. Anyways, for an update. I took out the Mobil 1 and put in Royal Purple 5W-30 with a Purolator PUREONE filter and the oil pressure seems more normal. Definetly not anywhere close to the meter limit which is good. As someone said before more pressure can mean a reduced flow rate. I'll try to get some specific numbers for you after my next oil change.

 

Nissan installed a new oil pressure relief valve under warranty due to high oil pressure (120psi at WOT) I picked up my car today and the psi is still 110-115psi. Nissan assured me that it is OK.

They notated on my receipt "Inspected oil pressure. removed oil pressure switch and installed mechanical oil pressure guage. Guage reads 50psi at idle and 120psi at 6000rpm. replaced oil pressure relief valve and retested. oil pressure drops 5psi average. consulted with tech line and told by tech that current oil pressure range is normal."

 

What brand of oil are u running? Also, do you let the car warm up (15 mins of driving under 4k) before you read the pressure guage?

 

Mobil 1 5W30 oil and nissan factory oil filter at every 2500 miles.
I always let the car warm up but not always under 4k rpm. but yeah I always go by the oil pressure at normal operating temps not cold.

 

I think the nissan filter could be an issue. I found must more stable oil pressure rates with the purolator PURE ONE. Im sure any high quality aftermarket filter is superior to the OEM one.

 

I'm not sure about that because i have used aftermarket oil filters before and I switched to a nissan filter because nissan told me to....... same problem.... anyway don't you think that if a factory filter was inferior they would make a better one or stop offering their current filter?

 

Sorry for the delay in getting back. I've been a bit occupied the last few months.

The current OEM Nissan filters have gone the way of Fram. They are constructed with the infamous cardboard endcaps that you can tear apart with your bare hands. Champion Labs filters, such as Mobil-1 still have the incredibly strong metal end caps, and a bypass valve that does not use cheap plastic in the critical parts as do Fram and OEM Nissan. I used a pipe cutter and cut apart examples of both to expose the insides, so I've seen this for myself. I've always been partial to the M1 products, and this is just another reason why I will stay this way and NOT follow Nissan's recommendation that you use their products. I just don't trust them.

 

I also have this same problem on an 05. I'm going to talk to a shop and see if there are any remedies...

I think the APS turbos are getting too much pressure, and I need some intervention to fix this!

 

spdkills
to fix the high pressure to turbo
just throw inline a reducer and that will limit pressure to turbo's

 

I was thinking of replacing the garret turbo restrictors... I was JUST on the road and I hit 90+ PSI @ WOT redline.

 

I've been reading this post, so i checked my own car and this is what i've found. I've been using Mobil 1 5w30 motor oil since about 1600 miles. My car oil pressure meter reads normal. Start up pressure starts at about 70 psi then settles to about 60 psi after warm up. This is at idle. I've been using OEM oil filter from the start. Oil changes are performed from every 1200-2500 miles or right after drag racing and or long hard trips around the island during annual cruises. I own a 2003 Track 350Z.

 

im using Mob1 syn 5w30 with KN filter... 03 N/A Touring

no probs with pressure

 

I just ran Mobile1 5w30 for the first time (after 30,000 miles), and my oil pressure is reading normal...60psi highway cruising.

 

Currently running 5W30 Mobil 1 with the M1 Oil Filter. Noticed a significant difference in oil pressure.
Cold: up to 120 psi under wot or near wot
Hot: around 60 psi under wot

Glad to hear that I'm not the only one.