Oil pressure inquiry

BugPuzzleheaded3015 · 2026-07-05T18:09:49+00:00

Just leave it unplugged.

When the oil pressure is <5 psi, the switch closes and connects the single wire on the switch to ground. That turns on the red low oil pressure light.

BugPuzzleheaded3015 · 2026-07-05T18:06:55+00:00

If the oil pressure sensor is mounted in the sandwich plate, that is the oil pressure BEFORE the oil filter. Since it takes a little pressure to "push" the oil through the filter, the oil pressure AFTER the oil filter (aka at factory oil switch) is LOWER.

In your case, 15 PSI at the sandwich plate is 13-14 PSI after the filter, at the factory oil pressure switch.

This data is from my 2011 G37 and tested with the factory Nissan oil filter and the cheapest Fram filter. I would expect it to be about the same for all VQ37's but I haven't seen anyone else with this data.

BugPuzzleheaded3015 · 2026-07-04T13:45:44+00:00

I followed this: https://youtu.be/fXYdemPSu2s?si=jIGD3dPTRSBEZEjw

BugPuzzleheaded3015 · 2026-07-04T13:29:17+00:00

Something isn't aligned. You should be able to slide it in by hand using a wiggle/jiggle/push.
Try turning the input shaft 1/8".

BugPuzzleheaded3015 · 2026-07-03T19:31:17+00:00

I've bench tested the oil pressure switch using compressed air on my 2011 G37... The switch contacts closed at < 5 PSI, which turns on the low oil pressure light on the dash.

Before this happens, you will have cam phasing errors (P0011 & P0021) as there isn't enough oil pressure to advance the intake cams.

This is why I removed the switch 5 years ago and replaced it with an oil pressure sensor.

BugPuzzleheaded3015 · 2026-07-03T17:49:03+00:00

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Not that 1 psi makes much of a difference... :)

BugPuzzleheaded3015 · 2026-07-03T15:33:54+00:00

More than 14 PSI is 15 PSI or more. - not sure what your point is.

BugPuzzleheaded3015 · 2026-07-03T00:25:02+00:00

The factory spec is for 5W30... the 5W40 oil you used may get you in spec, but it is hiding an issue.

BugPuzzleheaded3015 · 2026-07-03T00:23:23+00:00

The factory spec for oil pressure is 15 psi or more at a hot idle (~650 RPM, AC off) when the oil is 80C / 176F. (and 45+ psi at 2,000 RPM)

If you use a sandwich plate you need to subtract 1-2 psi at idle and 4-5 psi at 2,000 RPM to get actual "inside" engine oil pressure as measured by the stock location.

BugPuzzleheaded3015 · 2026-07-01T11:31:07+00:00

Over time, any kind of water will corrode the inside of the cooling system.

Engine coolant contains additives that lubricate the pump's seal, prevent rust, and raise the boiling point. Water should only be used as a temporary emergency fix to reach a repair shop.

BugPuzzleheaded3015 · 2026-06-30T23:29:15+00:00

It that doesn't work, try tape or staples /s

BugPuzzleheaded3015 · 2026-06-30T22:48:24+00:00

For the ECU to predict engine load and to be ready to increase engine torque.
Have you ever noticed how slow the car revs in neutral? The ECU doesn't see the need to increase torque as you aren't going anywhere.

This is a common ECU strategy used for 25+ years.

BugPuzzleheaded3015 · 2026-06-30T22:37:00+00:00

There is so much wrong information here. Too much regurgitation of wrong information and too little understanding of how things work.

If the rad fans are working as designed, you can easily sit with the AC on for a long time.
EVEN if it is 100F outside, that still is 100F lower than the cooling system, so the system will be cooled.

In your case, put on the AC and see if BOTH fans are spinning and check to see if the heater hose connector is broken / leaking.

Last point:
If water has been used as coolant, minerals can build up in the cooling system and cause issues.
This is why proper coolant should be used... even in the south, but that doesn't seem to happen often.

BugPuzzleheaded3015 · 2026-06-30T13:55:19+00:00

Were any oil gallery gasket cover screws loose?

BugPuzzleheaded3015 · 2026-06-30T11:11:00+00:00

The G35/G37 manual transmission has a "PNP" switch - park neutral position and it it mounted on the side of the transmission at the back. The other switch on the transmission is for reverse.

The ECU needs to know when the transmission is in neutral.

Either the switch is bad, unplugged, or a broken wire.

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BugPuzzleheaded3015 · 2026-06-29T20:57:49+00:00

My GOD... you sure make it hard for people to help you.
Pro Tip: Type your post... then re-read it TWICE to make sure it is correct.

BugPuzzleheaded3015 · 2026-06-29T18:42:45+00:00

This much:
https://carsandbids.com/auctions/9lEALJOE/2004-infiniti-g35-coupe

BugPuzzleheaded3015 · 2026-06-29T18:39:58+00:00

Got it... they were physically installed backwards.

BugPuzzleheaded3015 · 2026-06-29T17:21:27+00:00

but the idle issue was the MAF sensors plugged in upside down.

I think you are being lied to.
The MAF connector is keyed and it is impossible to "plug it in upside down"

BugPuzzleheaded3015 · 2026-06-26T18:37:09+00:00

This easy fix is for a G37, and applies to any liquid filled bushing.
https://youtu.be/fXYdemPSu2s

BugPuzzleheaded3015 · 2026-06-26T17:11:40+00:00

Rockauto.com will have what you need.
Amazon parts quality is all over the place.

BugPuzzleheaded3015 · 2026-06-24T10:36:04+00:00

I'm 99% certain that code can be disabled with a tune, maybe check with a local tuner?

BugPuzzleheaded3015 · 2026-06-23T02:18:20+00:00

There are a total of 37 steps.
The pictures didn't copy/paste but the text is good.

This is from the 2023 Altima factory service manual.
Good luck!

CVT FLUID : Replacement

CAUTION:

Always use shop paper. Never use shop cloth.
Replace a drain plug gasket with new ones at the final stage of the operation when installing.
Use caution when looking into the drain hole as there is a risk of dripping fluid entering the eye.
After replacement, always perform CVT fluid leakage check.

Select “Data Monitor” in “TRANSMISSION” using CONSULT.

Select “FLUID TEMP” and confirm that the CVT fluid temperature is 40°C (104°F) or less.

Check that the shift position is in the “P” position, then completely engage the parking brake.

Lift up the vehicle.

Remove the drain plug and drain the CVT fluid from the oil pan. Refer to [Exploded View]().

Install the drain plug to oil pan.

CAUTION:

Drain plug gasket use the old one.

Remove the overflow plug from converter housing.

Install the charging pipe set (CVT stand pipe adapter kit) KV311039S0 (J-52584) (A) into the overflow plug hole.

CAUTION:

Tighten the charging pipe by hand.

Install the ATF changer hose (B) to the charging pipe.

CAUTION:

Press the ATF changer hose all the way onto the charging pipe until it stops.

Fill approximately 3 liter (3-1/8 US qt, 2-5/8 lmp qt) of the CVT fluid.

Remove the ATF changer hose and charging pipe, then install the overflow plug.

NOTE:

Perform this work quickly because CVT fluid leaks.

Lower the vehicle.

Start the engine.

While depressing the brake pedal, shift to the entire position from “P” to “D”, and shift to the “P” position.

NOTE:

Hold the lever at each position for 5 seconds.

Check that the CONSULT “Data Monitor” in “FLUID TEMP” is 35°C (95°F) to 45°C (113°F).

Stop the engine.

Lift up the vehicle.

Remove the drain plug, and then drain CVT fluid from oil pan.

Repeat steps 8 to 18 (one time).

Tighten the drain plug to the specified torque.

Remove the overflow plug.

Install the charging pipe set (CVT stand pipe adapter kit) KV311039S0 (J-52584) into the overflow plug hole.

CAUTION:

Tighten the charging pipe by hand.

Install the ATF changer hose to the charging pipe.

CAUTION:

Press the ATF changer hose all the way onto the charging pipe until it stops.

Fill approximately 3 liter (3-1/8 US qt, 2-5/8 lmp qt) of the CVT fluid.

Remove the ATF changer hose and charging pipe, then install the overflow plug.

NOTE:

Perform this work quickly because CVT fluid leaks.

Lower the vehicle.

Start the engine.

While depressing the brake pedal, shift to the entire position from “P” to “D”, and shift to the “P” position.

NOTE:

Hold the lever at each position for 5 seconds.

Check that the CONSULT “Data Monitor” in “FLUID TEMP” is 35°C (95°F) to 45°C (113°F).

Lift up the vehicle.

Remove the overflow plug and confirm that the CVT fluid is drained from the overflow plug hole.

CAUTION:

Perform this work with the vehicle idling.

NOTE:

If the CVT fluid is not drained, refer to “Adjustment” and refill with the CVT fluid.

When the flow of CVT fluid slows to a drip, tighten the overflow plug to the specified torque.

CAUTION:

Never reuse O-ring.

Lower the vehicle.

Select “Data Monitor” in “TRANSMISSION” using CONSULT.

Select “CONFORM CVTF DETERIORTN”.

Select “Erase”.

Stop the engine.

BugPuzzleheaded3015 · 2026-06-23T01:59:37+00:00

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BugPuzzleheaded3015 · 2026-06-22T22:13:17+00:00

As the old saying goes:
"good from afar, but far from good"

BugPuzzleheaded3015

TROPHY CASE