Oil light on at idle when warm.

Slant 6 Engines

  1. John H.

    John H. Member

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    1967 225. Will a heavier oil help with oil light flickering at idle.
     
  2. Bad Sport

    Bad Sport HALF A BUBBLE OFF Staff Member FABO Gold Member

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    What's your idle set at? Sometimes just bumping up the idle a tad will take care of that.

    Of course if it hasn't been rebuilt then the bearing clearances may be an issue.
     
  3. George Jets

    George Jets 1967 Dart 2 Door FABO Gold Member

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    Slant 6s had issues with leaky oil send units, might want to try that.
     
  4. philip's66

    philip's66 Well-Known Member

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    I had a loose connection on my sender it would flicker on & off. Replaced it with a gauge. No more troubles& i know i have good oil pressure
     
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    • missing linc

      missing linc Loose nut behind the wheel FABO Gold Member

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      If you have a gauge, try checking actual pressure with it, sending units for the light rely on a spring inside which eventually gets contaminated with oil and send false signals. At the minimum, try replacing the sending unit, they're fairy cheap and simple to change. Heavier grade oil will help, but is only a band aid solution, and not good if you drive in cold weather.
       
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      • Mike69cuda

        Mike69cuda 64 is the new 17 FABO Gold Member

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        I run 20W50 in my old Trans am that has the same issue during the summer. No effort fix to the problem.
         
      • missing linc

        missing linc Loose nut behind the wheel FABO Gold Member

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        My 1990 Bronco was doing the same thing, checked with a mechanical gauge, it is a bit low, but a new sending unit installed and no more flickering light at idle, running 10w30 oil.
         
      • 69a100

        69a100 Well-Known Member

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        Not if your a couple/few quarts low on oil!
         
      • emsvitil

        emsvitil Well-Known Member

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        The pressure relief piston on the oil pump may be stuck open.
         
      • SGBARRACUDA

        SGBARRACUDA ROY FABO Gold Member

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        The light is designed to come on at Approximately 7 psi. I would venture to guess the oil pressure is low at normal running temperature. A mechanical gauge will clear this mystery right up.
         
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        • Slantsix64

          Slantsix64 Well-Known Member

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          Yes, Heavy oil does increase oil pressure.
           
        • slantsixdan

          slantsixdan =..=

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          Don't just throw heavy oil at it—not unless/until you're sure it's due to worn bearings. Other posters here are right: use a mechanical pressure gauge to find out what the oil pressure actually is at hot idle. If you don't want to go to the hassle, replacing the sender's a good bet; they tend to get lazy with age and can cry "wolf". And inspect the sender wire; if it grounds out anywhere along its length, the light'll go on.

          That said, it will also be a good idea to service the oil pressure relief valve to make sure it's doing its job, as described in these two threads: thread 1, thread 2. If that valve sticks partway open, it'll drop your oil pressure.
           
        • C130 Chief

          C130 Chief Mechanical Genius

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          As per Dan. Take the oil pump assembly off the engine and clean it out thoroughly especially the pressure relief valve. Sometimes they crud up and the relief valve sticks. If the engine has had sludge issues, drop the pan and clean the oil pump pickup.
           
        • barbee6043

          barbee6043 barbee 6043 FABO Gold Member

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          I always replace the light for a gauge if the pressure is questionable. Then you actually know whats what.
           
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          • RustyRatRod

            RustyRatRod Weenie idiot loser. FABO Gold Member

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            Oh hogwash. Stick with the original plan. Idle it up and run thicker oil. And if you think you hear a noise, turn the radio up. Why in the world would you want to diagnose anything and fix it right? That makes no sense at all.
             
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            • slantsixdan

              slantsixdan =..=

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              That's not quite as per Dan. There is no need to go to the (considerable) hassle of removing the oil pump from the engine.
               
            • Mike69cuda

              Mike69cuda 64 is the new 17 FABO Gold Member

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              Surprised nobody has mentioned the obvious......take the bulb out. Ha!
               
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