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Eep! my oil pressure keeps dropping??

Discussion in 'The Garage' started by Pookster, Sep 7, 2004.

  1. Pookster

    Pookster 1/2 ton status

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    When I got the truck, I ran at a nice consistant click above 40 (right in the middle). Cold startups were a little bit higher, but it always stayed at 40. This was after a fresh oil change on rotella T. 15w40., fram filter.

    The next oil change, I switched to Rotella T synthetic- And my oil pressure dropped a little, and dropped pretty low, almost 25% less while driving, and about 40% less at idle.
    This was with a FRAM filter.

    Decided I didnt need synthetic at this point (will use it again in winter). Switched to Mobil Delvac 15w40, and a mobil 1 filter. Same issue, and it seems the pressure might even be a little bit LOWER!

    The oil never seems to be diluted, but let me tell you, this delvac seems pretty thin compared to rotella T-, and about the same viscosity cold as Rotella synthetic.

    Any ideas? I dont mind the gauge being lower, as long as it isnt hurting my truck...
     
  2. Pookster

    Pookster 1/2 ton status

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    Anyone? /forums/images/graemlins/confused.gif
     
  3. big jimmy 91

    big jimmy 91 1/2 ton status

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    Bad sending unit , wiring prob.?
    Try a new sending unit , or do these guages ever gimp out?
    Does your oil ever smell like gas?
     
  4. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Do not trust an electric gauge to tell you how much oil pressure you have. As long as it's above zero, you know that you have oil pressure. That's all you're concerned with.

    Check any service manual and what's the first thing it says to check if your gauge registers low oil pressure? Remove the sending unit and screw in a mechanical oil pressure gauge.
     
  5. Pookster

    Pookster 1/2 ton status

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    Well, it always smells a bit like diesel, but I hear that is the norm. Beyond that.... Yeah,the oil pressure is still there, and it is higher when it is cold (which is also normal). Just that at idle, the oil pressure isnt that high anymore.
     
  6. big jimmy 91

    big jimmy 91 1/2 ton status

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    Ohh , it's diesel
    Do you let it idle for extended periods?
    If you do , a mech. told me that factory idle is too low , you need to bump it up to 1100-1200RPM
    He has put a hand throttle in his friends trucks and in the long run those trucks lasted considerably longer than those without(identical trucks)
    Apparently a diesel has such high compression that at a low idle it will allow blow-by past the rings and lead to oil contamination , premature wear to the engine
    Mabey this is why your oil will smell like fuel?
    Just a thought /forums/images/graemlins/thumb.gif
    BTW , I don't ever remember seeing a transport at low idle when parked at a truck stop , they are allways bumped up with a hand throttle (the older rigs anyway)
    I would suspect that your bottom end is starting to loosen up causing your low oil pressure , not a problem as long as it does'nt get any worse
    Good luck
     
  7. Pookster

    Pookster 1/2 ton status

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    It all happened after running 3000 miles on synthetic. Hopefully it didnt clean up too much!!! /forums/images/graemlins/rotfl.gif

    We'll see, it still runs good. I dont idle that much.
     
  8. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    It's a little bit of a pain because of the location of the sender on a 6.2, but the only way to be sure that your dash gauge is reading accurately is to spin out the factory sending unit and put a gauge like this

    [​IMG]

    in it's place. That being said, I'm sure there are other more convenient places on the block a guy could use to tap into an oil passage. Maybe PM Rene and ask him where you can throw a a gauge on to check oil pressure.......
     

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