Oil pressure loss and hybrid mode

Discussion in 'Hybrid General Discussion' started by mtown27, Jul 21, 2017.

  1. mtown27

    mtown27 TYF Newbie

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    I've got a 2008 Hybrid Yukon with 190,000 miles on her. She's recently started to have oil pressure issues on the gauge dropping below 40 at idle, and RPM drops below 1000 with a rough idle. I changed the oil pressure sensor behind the motor in 2015 but didn't know about the screen (didn't change it). The oil pressure is hit or miss. Sometimes the motor runs great all day, always going to Autostop at red lights and low speeds, and other times the oil pressure is always at or below 40 on the gauge. I did an oil change 500 miles ago with 5W-30. I'm stumped on what it could be. Plugs are relatively new and clean. Oil pump going bad? I've seen others pull the pan. I've also seen someone post about a 2nd sensor on the side of the oil pan. The rough idle and not going to hybrid is eating me alive!! Any thoughts?
     
  2. lt1gmc

    lt1gmc Member

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    Seems some with miles on them have had an issue with the oil pump relief valve sticking and bleeding oil pressure off when it sticks in bypass mode. That could explain why it is good sometimes and not others. Best to hook up a mechanical gauge to prove it is oil pressure or an electrical issue with gauge or wiring.
     
  3. Johan

    Johan TYF Newbie

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    When mine is hot, the oil pressure is always around 40 psi. The car works perfectly and the engine is incredibly soft. In the instruction it says that the pressure should be over 29 so just under 40 should not be any problems?
     
  4. mtown27

    mtown27 TYF Newbie

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    I bought the truck in 2012 and the oil pressure was always constant at the right needle mark. It stayed that way for 4+ years until recently. Now it flutters and drops way below 40 at idle. During normal driving it will go right back to the right needle mark. At idle it drops below 40 again. I’m changing the oil pump soon. Could be the pressure relief valve, could be something totally different. Trying to avoid an engine rebuild at 200,000 miles but it wouldn’t hurt.
     
  5. MPAWill

    MPAWill TYF Newbie

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    My first post. I gave up on forums 5 years ago but im back because I may be able to help someone lol

    I have a 09 hybrid tahoe 110k and I had oil pressure issues. Had!

    1st. Oil pressure was on zero, Guage on zero didnt move. No check engine light. Fix: changed oil pressure sensor.

    2nd (1year later) low oil on dtc, Guage on 20 and below. Oil in motor. Stealership said head gasket and wanted 6.5k(another story) i changed oil, filter, oil pressure sensor, sensor filter, with no change. Read on one of the forums the pick up tube o ring goes brittle and sucks air and oil which leads to low oil pressure readings so I changed it.fix: oil pickup tube and oil pan gasket using the instructions on a Cadillac Escalade someone posted and as of the last 4 weeks oil pressure is back above the center needle and idling like a brand new truck. hopefully this helps this gave me nightmares but everything is back to normal now. I literally thought I was going to have to sell my truck which I didn't want to do but I fixed the issue Feel free to ask any questions you need to I know the process inside and out

    Will
     
  6. jprevost

    jprevost TYF Newbie

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    Check that adding oil doesn't fix the problem. I have a cracked oil pick-up tube o-ring that has caused this same issue. Because it's a 4x4 and because they didn't design the pick-up tube flange to be bolted from the front, it's very difficult.
    Good luck.
     

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