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oil pressure sending unit?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 4x4blazer, Oct 21, 2001.

  1. 4x4blazer

    4x4blazer 1/2 ton status

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    My 350 might has 1000 miles on it at the most and I just noticed my oil pressure drops to nothing after the engine gets warmed up. When I first crank it up the pressure reads fine. The level is good. And the temp and engine noises are all normal. The sending unit is off of my old engine, and I was hoping that it might be the culprit. Any ideas?
     
  2. Pugsley

    Pugsley 1/2 ton status

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    Sounds like the sender to me - they're cheap anyway, so I'd go ahead and change it and see what happens.

    Of the 5 toughest dogs in the neighborhood, my cat's ranked #3
    <a target="_blank" href=http://pugsley.alloffroad.com>pugsley.alloffroad.com</a>
     
  3. backlash

    backlash 1/2 ton status

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    I agree. If you wait long enough ... it'll register less and less. Enentually it'll read what mine does ... ZERO!

    LOL! I need a new motor eventually, but it runs so strong now ... 180,000+
     
  4. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Just get a mechanical gauge you can trust and solve your problems forever.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  5. Dip Stick

    Dip Stick Registered Member

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    What should the pressure be normally? Mine always reads inbetween 0 and 15 so i think something is wrong

    <font color=red> It's not what you drive, it's how you drive it</font color=red>
    1986 K20 & Lots of Rust
     
  6. Pugsley

    Pugsley 1/2 ton status

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    Same problem most likely - around 30 is average for idle.

    Of the 5 toughest dogs in the neighborhood, my cat's ranked #3
    <a target="_blank" href=http://pugsley.alloffroad.com>pugsley.alloffroad.com</a>
     
  7. yeild2me

    yeild2me 1/2 ton status

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    "..for high performance applications 10 psi per every thousand rpm's of usable horsepower..."

    this is what they told us when i went to Wyoming Technical Institute back in 91. so, 10 psi at idle is fine, 25 psi at highway speeds. a little lower than i like, but that is just the "golden rule" as i was taught. personally, i like it at LEAST 30 at idle, and 45 at highway.

    my .02

    350 TBI, 700R-4, NP241, D44-14FF, 4:10's, 38.5 TSL/SX's, full conv., full cage
    <a target="_blank" href=http://www.yeild2me.rockcrawler.com>www.yeild2me.rockcrawler.com</a>
     
  8. chevyracing

    chevyracing 1/2 ton status

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    If the sending unit is showing a lower reading after it warms up the first thing to do is buy a mechanical unit and see if it still happens. If the problem continues then hook the sender up to the front of the block above the t-chain cover at the little plug and put the mechanical unit on the rear. That will tell you if you have a line plugged up in the rear with some debris. If you still have a low reading remove the oil filter and check the bypass spring and make sure it is not stuck open. If all this does not work then you have a problem... More than likely you have too much clearance between the crank journal and the bearings. Did you plastigauge the bearings before you assembled the engine? If not, shame on you.
    The most likely cause is the last thing I described to you. Too much oil clearance will do that more often than anything else..... Good luck...

    John

    Like to go sloppin' 'round in da mud in a rapid fashion....=) [​IMG]

    <a target="_blank" href=http://community.webshots.com/user/chevyracing>http://community.webshots.com/user/chevyracing</a>
     

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