Oil pressure issue, oil pressure dropped while driving out of nowhere

DAVID LEWIS4

MEMBER
2005 HUMMER H2
6.0L
V8
4WD
AUTOMATIC
130,000 MILES

No knocking or engine noise at all so drove 5 miles to my house. Still no noise. Gauge keeps constant 22 psi while driving and 0-5 while idling. Replaced oil sending unit, still same problem, I have driven 25 miles since first warning with no engine noise, knocking etc. I do have rear main seal leak and a horrible front differential leak. I need help diagnosing issue. What should I do next?

5 Replies

DANNY L

MECHANIC
5,648 POSTS

Hello, I'm Danny.

The first thing I would do before actually changing the oil pump/tearing apart would to get a mechanical oil pressure gauge and tap into where the sending unit you replaced to verify the oil pressure. If you do that and the pressure is the same as on the instrument cluster readings then I would suspect a faulty oil pump. Let me know if you have any further questions on this issue. Hope this helps and thanks for using 2CarPros

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Tuesday, December 3rd, 2019 AT 12:57 PM

DAVID LEWIS4

MEMBER
3 POSTS

Okay, i'm going to get an oil pressure gauge. Do you think maybe dropping oil pan first and checking pick up tube and screen? Man I have already done so much work on this thing. Everything seems to be giving out at the same time. My luck man.

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Tuesday, December 3rd, 2019 AT 12:59 PM

DANNY L

MECHANIC
5,648 POSTS

Hello again.

I just figured that you could do that first to verify the readings before having to tear apart anything. It must have been a flawed pump or design as that being a common problem in the mid 2000's GM vehicles. If you need me to supply oil pump replacement instructions I will. Thanks again for using 2CarPros.

Danny-

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Tuesday, December 3rd, 2019 AT 1:17 PM

DAVID LEWIS4

MEMBER
3 POSTS

But if it's the oil pump, how am I still driving it? I have put 30 miles on it since it first said low oil pressure? That's what is throwing me off. No way I could drive it with a bad oil pump surely, that's why i'm stumped. This year model doesn't have the screen filter under the sending unit does it? That's what I thought the problem was to begin with. I didn't replace that just the OSC.

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Tuesday, December 3rd, 2019 AT 2:08 PM

DANNY L

MECHANIC
5,648 POSTS

Hello again.

Like I stated this was a common problem for mid 2000's GM vehicles. Something internally happens and runs them low on pressure. Not completely failed, just low on pressure. If you want to forgo the mechanical gauge test I've attached the step-by-step oil pump replacement instructions below. Hope this helps and thanks again for using 2CarPros.

Danny-

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