Low Oil Pressure, Part Duex II: Am I wrong?

Discussion in 'GMC Truck Forum' started by SQBADOG, Jan 7, 2018.

  1. SQBADOG

    SQBADOG Full Member

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    On 2005 GMC Yukon XL Denali 6.0 L I have been chasing the low oil pressure for a while. Have finally been able to associate a pattern with this. When the weather started getting colder, I would get low oil pressure on start-up. I replaced the sending unit, no good. Other video's show a filter beneath the pressure switch that can cause this, but this does not start till 2007.

    After the car warms up, good oil pressure. So long story short, that means it's a seal. How am I so sure? Few years ago my Kubota Diesel Tractor hydro static transmission stopped working when it got cold. Would put it in the garage, let it warm up, and it worked. A guy in Northern Canada on the Kubota forum had me add a seal adaptive I never heard of, that was 2011, tractor still works like new today.

    I added the seal additive, and it has greatly improved, but it still needs to be replaced. So there are two areas for the seal. The easy place, is the pick-up tube or-ring. The hard place, the two o-rings n the oil pump. So the logical plan would be to drop the plan, and replace that o-ring, but I guess unless i's a total failure, you could not tell and would have to move on to the oil pump. Any other options?
     
  2. scavanger

    scavanger Full Member

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    If you have the pan off,wouldn't it make sense to replace the O rings in the pump too? why take the chance.And if high mileage, check a rod bearing ?
     
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  3. leolkfrm

    leolkfrm Full Member

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    maybe the relief valve on oil pump is sticking?
     
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  4. MikeG

    MikeG Full Member

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    Is the pressure issue only happening when the weather gets cold? If so, Oil weight..........?
     
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  5. gmctrucks

    gmctrucks Full Member

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    Listen at 1:40 on the video it just might be that your truck has the same problem good luck.



     
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  6. SQBADOG

    SQBADOG Full Member

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    I have dropped the pan, here is the o-ring. Doesn't look that bad. Soooo I'm now of to the taking the front of the engine off. IMG_3422.JPG IMG_3424.JPG IMG_3427.JPG IMG_3427.JPG IMG_3424.JPG IMG_3422.JPG
     
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  7. SQBADOG

    SQBADOG Full Member

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    Yup, saw that, and its getting a new oil pump...and a new timing chain and water pump....have it apart, might as well get it done....while your in....
     
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  8. SQBADOG

    SQBADOG Full Member

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    No. This is a common problem on these engines. Put Lucas oil in, no change wither way.
     
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  9. SQBADOG

    SQBADOG Full Member

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    So tomorrow the oil pump comes out. You can see the o-ring does not look that bad. So I am hoping you can validate the stuck valve on the pump? It would be nice to know before I put it all back together....
     
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  10. SQBADOG

    SQBADOG Full Member

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    So, about to remove the Harmonic Balancer....with the Chrysler remover....I see that I have to remove the starter. Question. Hard to tell, but looks like original starter. Replace it while its out? Also the all data sucks on this, but looks like going to get out the old 39" snap-on breaker bar to break the bolt off...figuratively of course.
     

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