Low oil pressure

2002 CHEVROLET 1500
204,626 MILES • 5.3L • V8 • 4WD • AUTOMATIC
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CAYDEN STEPHENS
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So I just put in a motor that has 86,000 miles on it. it was pulled from a wrecked truck so they put it in and now my oil pressure is super low; reading 15 PSI to 10 while hot 20 25 ish while cold. they put a brand new sensor on, new oil pan gaskets and the oil pump should be fine because it’s fairly new. my thing is, it sounds great, runs fine and doesn’t overheat. anybody know the reason for the low oil pressure?
May 22, 2021 at 4:39 PM
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JACOBANDNICKOLAS
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Hi,

The first thing I would recommend (if it hasn't been done) is to check the pressure using a mechanical oil pressure gauge. Since the one in the vehicle is electric, there could be excessive resistance in the wiring or simply a connector issue.

To do this simply requires a mechanical test gauge. Most parts stores will lend one to you. When you get it, simply remove the electrical oil pressure sensor and screw in the mechanical one. That will give you a good reading as far as what the engine is producing.

Try that and let me know what you find.

Joe

May 22, 2021 at 9:35 PM
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CAYDEN STEPHENS
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Hey thanks for the reply, but I have a question. if you was really only running 10-15 PSI oil pressure wouldn’t you hear noises in your engine like lifters etc., since the pressures so low.
May 23, 2021 at 10:58 AM
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JACOBANDNICKOLAS
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That's a good question to ask. Honestly, it isn't below what the manufacturer indicates as a problem, so even though it is low, it won't likely make noise. With the engine hot and at idle (1,000 RPMs) the minimum recommended is 6 PSI.

If you look at the pic below, it shows what the minimum readings should be with the engine at operating temperature and at specific RPMs.

Let me know if this helps or if you have other questions.

Take care,

Joe

See pic below.

May 23, 2021 at 7:07 PM
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CAYDEN STEPHENS
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So I got an update apparently it’s all the pressure the motor has they basically told me it’s fine and it will only get 10 PSI per 1,000 RPMs. they said it’s the way the motor is doesn’t make sense to me, but they said it’s fine to drive it should be enough oil pressure.
May 25, 2021 at 6:46 AM
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CAYDEN STEPHENS
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So I got an update apparently it’s all the pressure the motor has they basically told me it’s fine and it will only get 10 psi per 1000 rpm they said it’s the way the motor is doesn’t make since to me but they said it’s fine to drive it should be enough oil pressure
May 25, 2021 at 6:46 AM
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JACOBANDNICKOLAS
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Hi,

Yep, that's what I expected. The only thing I recommend is to make sure you keep the oil clean and full. It's hard to believe that the manufacturer indicates 6psi okay at 1,000 RPMs. It does seem a bit low, but that's what they indicate.

If something changes or if you have other questions, please feel to let me know.

Take care,

Joe
May 25, 2021 at 8:26 PM