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oil pressure should be?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by beefjerky, Apr 17, 2002.

  1. beefjerky

    beefjerky Registered Member

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    86 k5 with stock 350/700r4/np208. what should the oil presure read? my needle on the gauge keeps bobbling between 30 and 60. what causes this?
    thanks
     
  2. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Don't depend on an electric guage to be accurate...
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    I believe you could measure resistance between the sending unit and the block, to see if its gauge or sender. Even then, I don't think there is an accurate way to tell if the sending unit is bad or if the oil pressure is actually varying, short of a mechanical gauge (even though they are still gauges requiring calibration).

    A "coincidence" I've noticed is that bad sending units rattle quite loudly when shaken if they have failed. Not sure if thats universal or not, but all the ones I've had that have rattled, did not work.

    I replaced the sending unit on my truck, the needle jumps very slightly at idle now (better than before) and I've swapped three gauges 'cause I had spares. It's not the gauges, and I doubt its the sender, I think the oil pump is getting sloppy. I would say typical is 30 or slightly less at idle, and 30-45 cruising. "Safe" idle is claimed to be as low as 5PSI hot, but obviously if you are down that low, you've got some problems.

    Mines started idling at 15PSI hot, and making some noise...hope the machine shop gets my balance job done so I can pull this motor out before a bearing decides it needs to move.
     
  4. fortcollinsram

    fortcollinsram 1/2 ton status

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    My gauge is almost always pegged at 60...when it gets nice and hot, it drops below 60 a bit at idle...I think my factory gauge is the biggest problem...

    Chris
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Well, you gotta troubleshoot to be sure. I'm constantly amazed that Chevy truck owners seem to be the only ones with stock gauge problems, yet almost all other GM vehicle owners have NO complaints, except visibilty with stock gauges.

    My dads K20 454 also pegged at 60 and stayed there all the time. When he got a stock 80PSI unit and the correct sending unit (yes there are two different sending units AND gauges) it was confirmed that PSI was actually that high, the 60PSI gauge and sender simply couldn't indicate that high pressure.
     
  6. greatwhitenorth

    greatwhitenorth 1/2 ton status

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    Mine stays pegged right about the 40psi mark.. 350 with about 200k miles.
     

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