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Dropping oil pressure?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by JeremyK5, May 8, 2003.

  1. JeremyK5

    JeremyK5 1/2 ton status Premium Member

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    I just recently installed a mechanical oil pressure gauge, and I don't like what I'm seeing. When the motor is cold, the pressure is roughly 20psi idle/ 55 psi driving. After 15-20 min. of driving the pressure drops to roughly 1-2psi idle /forums/images/graemlins/eek.gif / 25psi driving. The motor doesn't sound noticably louder when the pressure is low, but my leaking exhaust could be drowning small noises out. The oil is fresh valvoline 20w50 and a new fram X2 oil filter.

    Does anybody have any idea what I should check first? /forums/images/graemlins/1zhelp.gif

    Jeremy
     
  2. 85 Shortbox

    85 Shortbox 1/2 ton status

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    I had that problem in my ford daily driver, turned out to be the oil pick up tube kept blocking up. Good luck.
     
  3. 87sm465np208

    87sm465np208 1/2 ton status

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    id put a delco oil filter on that thing or perhapes a WIX at the best. /forums/images/graemlins/thumb.gif

    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/truck.gif
     
  4. SUBFAN

    SUBFAN 1/2 ton status

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    Smell the oil for gas....An old pontiac I had the fuel pump went bad and dropped gas into the oil. Gotta love those pressure gauges....

    See if gauge is mounted correctly, no kinks blockages in the line, if all that is good, I would say it is time for a tear down.... /forums/images/graemlins/frown.gif
     
  5. bee32

    bee32 1/2 ton status

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    Or actually it could just be that the gauge is reading correct. How old is your oil pump? Might need to look at going to a high output oil pump. Mine does the same thing and that is what I am going to do as soon as I get alittle time to get it done.
     
  6. 83PJW

    83PJW 1/2 ton status

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    oil pressure sould drop a little when the motor gets hot. i dont think buy 15 or 20 though. 20 psi is good at an idle.a good way to check is the mechanical guage you just put in take the small plasctic tube off the adapter piece and start up the motor. it will either pour oil out (good thing) or drip out (bad thing). do that first cold then re attach it and warm up your motor. do the exact same thing and see the differance. its a pain in the ars but it works.
     
  7. JeremyK5

    JeremyK5 1/2 ton status Premium Member

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    [ QUOTE ]
    I had that problem in my ford daily driver, turned out to be the oil pick up tube kept blocking up. Good luck.

    [/ QUOTE ] If it doesn't turn out to be a simple problem, that will be the first thing I'll check.

    [ QUOTE ]
    Smell the oil for gas....An old pontiac I had the fuel pump went bad and dropped gas into the oil. Gotta love those pressure gauges....

    See if gauge is mounted correctly, no kinks blockages in the line, if all that is good, I would say it is time for a tear down....


    [/ QUOTE ] The oil is still fairly clean and doesn't smell like gas.
    The block is out of a motor that was rebuilt and the person cracked a head, so my previous owner put on a set of heads he had laying around and installed it in the Blazer. This was about 10,000 miles ago, so hopefully the bottom end is still good.

    [ QUOTE ]
    Or actually it could just be that the gauge is reading correct. How old is your oil pump? Might need to look at going to a high output oil pump. Mine does the same thing and that is what I am going to do as soon as I get alittle time to get it done

    [/ QUOTE ] If I don't find any obvious problems, like bad bearings, I'll try that since I'm not %100 sure that the oil pump is good.
    [ QUOTE ]
    oil pressure sould drop a little when the motor gets hot. i dont think buy 15 or 20 though. 20 psi is good at an idle.a good way to check is the mechanical guage you just put in take the small plasctic tube off the adapter piece and start up the motor. it will either pour oil out (good thing) or drip out (bad thing). do that first cold then re attach it and warm up your motor. do the exact same thing and see the differance. its a pain in the ars but it works.


    [/ QUOTE ] That would be great if it was just a gauge problem, I'll try your test tommorrow.

    Thanks for all the help, I'll let you guys know what I find out.
     

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