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Oil Pressure Gauge Reading Question


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#1 the red zed

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Posted 20 September 2016 - 09:28 PM

Hi Gents,
It came to my attention the oil pressure gauge sits below 1/4 while idling at 1000rpm. Is this pretty normal for L motor or is time to replace the oil pressure sender? Some engine builder did mentioned L motor are prone to loose internal oil pressure.. Cheers

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Edited by the red zed, 20 September 2016 - 09:44 PM.


#2 Linton

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Posted 20 September 2016 - 09:47 PM

looks about right for idle on an old engine, does is rise with increase in rpm? best bet is to install a proper oil pressure gauge and compare the readings, when I got my 300zx it showed very low oil pressure I panicked on the way home turned out to be a faulty pressure switch.



#3 the red zed

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Posted 21 September 2016 - 07:14 AM

It rises up to about 1/3 when sits around 3.5K. I might have a pressure switch out of toyota 18rg that I could possibly stick in to test. Cheers Linton.


looks about right for idle on an old engine, does is rise with increase in rpm? best bet is to install a proper oil pressure gauge and compare the readings, when I got my 300zx it showed very low oil pressure I panicked on the way home turned out to be a faulty pressure switch.



#4 Agno

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Posted 21 September 2016 - 12:31 PM

Perfectly normal, mine sits about there at idle and rises when driving.

 

It is also dependent on the oil level in the engine (less oil reduces oil pressure). Before I stopped the sump from leaking I used to use the oil pressure gauge as a barometer for when it was time for a service lol



#5 the red zed

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Posted 21 September 2016 - 07:14 PM

Perfectly normal, mine sits about there at idle and rises when driving.
 
It is also dependent on the oil level in the engine (less oil reduces oil pressure). Before I stopped the sump from leaking I used to use the oil pressure gauge as a barometer for when it was time for a service lol


Hi Agno, many thanks for the info & good to know it's pretty normal at such. The dipstick seemed showing good oil level. I might do an oil change soon with slightly thicker oil like 20-50w to see any improvement.

#6 Linton

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Posted 21 September 2016 - 09:13 PM

you could put a new oil pump in very easy to change, just need to get the motor on TDC before you remove the pump so your timing is not  altered, lift of dist cap and mark where the rotor is pointed remove and refit the new oil pump (you will need to drop the sway bar) check your marks then check timing good to go. putting thicker oil in to remedy low oil pressure probably wont hurt  the engine but why not fix it properly, if it does in fact have low oil pressure.


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#7 Cozza

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Posted 21 September 2016 - 09:27 PM

What viscosity oil are you currently running?
Is the gauge reading 1/3 when the oil is both cold and hot?
Maybe chuck a known gauge on in place of the sender unit to be confident about the pressure under different conditions.

This would eliminate:
A dodgy sender
Possible poor electrical connection
A dodgy gauge

Good luck.
Mick
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#8 gilltech

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Posted 22 September 2016 - 12:22 PM

FWIW I've always understood the oil pressure sender units to have a rather chequered history when it comes to reliability & providing accurate gauge readings, I've certainly found that with my own car.


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#9 the red zed

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Posted 22 September 2016 - 08:32 PM

What viscosity oil are you currently running?
Is the gauge reading 1/3 when the oil is both cold and hot?
Maybe chuck a known gauge on in place of the sender unit to be confident about the pressure under different conditions.
This would eliminate:
A dodgy sender
Possible poor electrical connection
A dodgy gauge
Good luck.
Mick

I agree as it's the easiest & quickest way of troubleshooting for a start. It seemed gauge level read just about the same regardless hot or cold conditions. To be honest I have nil clue of the existing oil viscosity as it already had it in by previous owner but it certainly could use a change now. Cheers

Edited by the red zed, 22 September 2016 - 08:44 PM.





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