Oil pressure sensor location my oil gauge had been fluctuating between 15-40 psi

DJONESII

MEMBER
1995 CHEVROLET SILVERADO
V8
2WD
AUTOMATIC
175,000 MILES

My vehicle has 175K miles on it, but I changed out the engine with a new crate engine at 100K miles. I didn't change out all the sensors, but most of them.
My oil gauge had been fluctuating between 15-40 psi and was very resposive to fluctuations during pedal movement. I figured the Oil Pressure Sending Unit needed changed. So I changed it. Now the engine shows close to 80 psi and stays high until the engine warms up. Then it drops to around 50-60 psi.

Any ideas as to what is causing this or is this okay to continue driving?

4 Replies

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Actually, that sounds normal especially if you live in an area that is cold. At start up, the oil is heavier which produces more pressure. Have you ever heard any ticking or knocking from the engine? Here is the oil pressure sensor. Check out the diagrams (Below). Please let us know what happens.

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Saturday, May 1st, 2021 AT 1:54 PM

DJONESII

MEMBER
2 POSTS

I've not heard any valve noise chatter. My truck does have headers on it, and noticed a noise coming from the underside of the engine (on the drivers side) that sounds exactly like a collector leak. I've changed not only the collector gaskets, but also the header to manifold gaskets. The noise is a slow (solo) tick that appears to go with the the flow and rythem of the exhuast. The time of year that I replaced the sender unit was in the summertime. Oil pressure at 80psi was about a 90 degree day. Didn't drive long because I wanted to make sure I didn't have clogged screen, releif valve or oil pump.

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Saturday, May 1st, 2021 AT 1:54 PM

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

You're the first person that I ever talked with that knew there was a relief valve for the oil pump. THe filters are rated up to 150 psi. (Which you don't want) 80 is high, but not too high to worry about. As far as the pick up screen, if it was plugged, you would lose pressure so that should be fine. If it continues to climb, then I would consider the relief valve. I have actually seen filters that were shapped like softballs from too much pressure. But they never let loose.

What you described sounds like a header leak. Once you have exhausted that, let me know if the noise is still there. Remember, too much pressure isn't what you want, but it won't starve the engine of oil unless the filter lets go.

Let me know what you find of if you have other questions.

Joe

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Saturday, May 1st, 2021 AT 1:54 PM

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Sorry, I just reread your posting. The exhaust is alread taken care of. Does the sound seem to be a rod or main noise? Could it be a wrist pin?

Sorry I missed that.

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Saturday, May 1st, 2021 AT 1:54 PM