What Classifies As Low Oil Pressure? 2010 370z

[kiwi370z]

2010 370z. 83,500 miles / 134,500 kms automatic.

Purchased from a second hand car dealer, in very good condition.

I have had the car for 7 days, and installed a 150 PSI oil pressure gauge today. During this 7 days I've not had the stock oil pressure warning light come on at all.

I've tested the oil pressure with the car on the ground at idle and at 2,000rpm with results as follows:

Oil temperature 80*c (based on stock gauge on dashboard) + Idle RPM in "Park" = 7-8 PSI oil pressure
Oil temperature 80*c (based on stock gauge on dashboard) + 2,000 RPM in "Park" = 36 PSI oil pressure


I don't know what oil is in there currently, but it is new, as the dealer had it serviced prior to me purchasing it and visibly checking the oil it is clear/new looking.

Questions:
How much does a different weight of oil affect oil pressure PSI results?

Are these results of concern?

[Rusty]

The 370Z does not have a oem oil pressure gauge. The gauge on the left of the 3 cluster gauges on the dash is an oil temperature gauge. You said that you installed a oil pressure gauge. What does that read? Also where did you install the pressure sending unit?

[kiwi370z]

Originally Posted by Rusty

The 370Z does not have a oem oil pressure gauge. The gauge on the left of the 3 cluster gauges on the dash is an oil temperature gauge. You said that you installed a oil pressure gauge. What does that read? Also where did you install the pressure sending unit?

I think you misread.

You are correct, the 2010 370z does NOT have an oil pressure gauge. But it does have an oil temperature gauge and an oil pressure fault sensor.

I installed an aftermarket oil pressure gauge/sensor, and left the stock oil temperature gauge as is.

I unthreaded the stock oil pressure fault sensor, and used an adaptor like below to fit the stock oil pressure fault sensor and aftermarket oil pressure gauge sensor together.

[Rusty]

Missed part of that. Sorry.

I have my sensor in the same location. You're low on oil pressure. You might have a oil galley failure. The only sign that it failed is low oil pressure. or when the engine starts to eat it's self. The warning light doesn't come until 5 to 10 psi. After it's too later.

Here's a thread I started about oil pressure.

Observed Oil Pressure with a gauge

[JARblue]

7-8 psi at idle is pretty dang low. I would expect that your gallery gaskets are compromised. You'll probably see pieces of the gasket blown out or find some bits of gasket in the bottom of the oil pan. Recommend replacing them with the EPS kit that includes new hardware.

[SonicVQ]

This is going to seem like an odd question, but is your 370 "sunset orange" (that was blue?)

[Rusty]

Originally Posted by SonicVQ

This is going to seem like an odd question, but is your 370 "sunset orange" (that was blue?)

[kiwi370z]

Originally Posted by SonicVQ

This is going to seem like an odd question, but is your 370 "sunset orange" (that was blue?)

No, it's a fresh import from Japan in white.

[SonicVQ]

Originally Posted by kiwi370z

No, it's a fresh import from Japan in white.

Got it.
I saw an orange 370 at the Golden Cross Hillclimb on Monday and was wondering if it was you.
The roads in NZ are the most fun I have ever driven on!

[husam2012]

I honestly would recommend a new engine to be swapped at that point. There's no doubt that you started wearing the bearings with such low oil pressure. No point in doing gallery gasket now.

[kiwi370z]

Originally Posted by husam2012

I honestly would recommend a new engine to be swapped at that point. There's no doubt that you started wearing the bearings with such low oil pressure. No point in doing gallery gasket now.

How likely is this to be a problem?

How much more work is it to check for that, while doing the gallery gasket work?

I had Nissan do a pre-purchase inspection on the vehicle before I purchased it from another dealer. The Nissan tech said the engine felt/looked very healthy, and the compression checks were great.

[kiwi370z]

I've been doing some more thinking about this, while I await quotes from shops to investigate and/or repair.

If I genuinely had low oil pressure, why has the low oil pressure warning light never appeared on the dashboard? And why does the computer not have any fault codes?

Is it possible that if the STOCK oil pressure fault sensor fails, the computer then won't show an oil pressure warning light? Or if it detects NO signal at all from the stock warning sensor, does it automatically show a warning light?

[JARblue]

The oil pressure warning light is pretty much useless. It's literally just a fault code if the signal goes low enough (so yes the dash light should come on if the sensor fails). From what I can tell it comes on at about 5 psi - if it comes on you'll be lucky if you haven't damaged the engine.

[husam2012]

Originally Posted by kiwi370z

How likely is this to be a problem?

How much more work is it to check for that, while doing the gallery gasket work?

I had Nissan do a pre-purchase inspection on the vehicle before I purchased it from another dealer. The Nissan tech said the engine felt/looked very healthy, and the compression checks were great.

You would have to take out a couple bearings and see if they're still good, but at that point you might aswell change all the bearings and in the end swapping in a newer block is cheaper $ wise.

Edit: The reason I'm saying this is I had a friend's car that we did the gallery gasket on. Oil pressure was a little higher than yours but still under 13~ psi at hot idle. His engine is still running but the oil is glittery with every oil change.

[sirnixalot]

First step for me would be to drain the oil as slow as you can through a coffee filter with a nice strong magnet in it, this will take a while but the information you gain from it is worth it.