# Oil Pressure Fluctuating



## eastcoastjava (Apr 2, 2011)

So today i noticed that my oil pressure is fluctuating between 24( At an idle) an 38 while driving? I do know that Oil pressure does fluctuate with the difference of RPMS but is this a safe level for my truck, i ask this because i am so used to constantly seeing the oil pressure gauge sit around 40. The truck is an 04 sierra 2500 HD 6.0L gasser, i just picked it up 3 weeks ago.


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## White Gardens (Oct 29, 2008)

Absolutely normal.

Had a 4.3 that ran it that range.

Have an 8.1 that runs in that range.

Pretty standard for most GM motors.



..............


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## ceptorman (Nov 30, 2011)

Like White Gardens said it's normal for your gauge to fluctuate like that. I will add, if your low oil pressure warning light comes on, stop the motor immediately. My 06 Chevy 1500 with a 4.8 had a slightly lower than normal oil pressure one day, I noticed it and kept an eye on it, drove it half a day like that. Next morning, my low oil warning came on, instantly turned engine off. It's rare, but an o-ring on the oil pump came off and lost prime. I did the required oil pump check of connecting a gauge to oil sending unit, and running engine up to temp, well that killed the engine...no oil pressure! The good news...I did replace engine with a low mileage one, runs great now.


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## theholycow (Nov 29, 2002)

ceptorman;1580961 said:


> I will add, if your low oil pressure warning light comes on, stop the motor immediately.


Also, if your oil pressure gauge seems like it's broken because it's indicating something that can't possibly be happening in the engine...

I was sure the gauge couldn't be fluttering from 0 to max so fast it's a blur like hummingbird wings unless it was a problem with the gauge sender itself, then that Ford 460 crapped the bed.


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## ceptorman (Nov 30, 2011)

theholycow;1581015 said:


> Also, if your oil pressure gauge seems like it's broken because it's indicating something that can't possibly be happening in the engine...
> 
> I was sure the gauge couldn't be fluttering from 0 to max so fast it's a blur like hummingbird wings unless it was a problem with the gauge sender itself, then that Ford 460 crapped the bed.


That's a bad feeling isn't it?


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## White Gardens (Oct 29, 2008)

theholycow;1581015 said:


> Also, if your oil pressure gauge seems like it's broken because it's indicating something that can't possibly be happening in the engine...
> 
> I was sure the gauge couldn't be fluttering from 0 to max so fast it's a blur like hummingbird wings unless it was a problem with the gauge sender itself, then that Ford 460 crapped the bed.


It can happen.

When my old 6.9 diesel finally grenaded the motor, I had the oil pressure drop and flip back up rapidly a couple of times.

I knew something was amiss, and it did the drop to zero and back up again about a dozen times. I kept plowing along. Truck was old and nasty.

I barely got the truck home as it started to loose power and sounded horrible. Got it into my driveway to see oil leaking out the rear main.

My mechanic said I probably spun a bearing.

...........


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## Plowtoy (Dec 15, 2001)

That's a little on the low pressure side for my taste. You may just have a warn sending unit (sensor) or you could just have a warn out engine. I think the first thing I would try is a heavier engine oil, maybe a conventional 10w40, 15w40, or even 20w50 to see if it brings it up closer to 40 while idling hot. If you are running synthetic it 5w30, it may bring your pressure to the numbers you indicated. I personally run synthetic 15w50 in both my wife's 02 impala and my 03 Tahoe and the Tahoe has 35 at idle hot and 60 while going down the road.
The other thing to remember is that the instrument clusters go bad all the time in these things. I just had the Tahoe's rebuild because the speedo jumped around and stuck at 70 and the oil pressure was all over the board. I used www.gmgaugerepair.com and have been real happy with it...


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## eastcoastjava (Apr 2, 2011)

Yea im not that worried about it, i have a 48000 mile warranty on it, which covers the engine as well as electronic panels if they die out.


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## Cooter24 (Nov 13, 2007)

10psi/1000rpm was the old standard. Most now say 6 is plenty.


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