High silicon content in oil

Discussion in 'Engine & Drivetrain' started by clandr1, Aug 5, 2018.

  1. clandr1

    clandr1 Full Access Member

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    Hi everyone,

    I've sent four oil samples to Blackstone Labs over the last 3 years, and each time my silicon readings have been higher than universal averages (see bottom row of the attached picture). The techs at BL have suggested checking the air intake system for cracks or leaks, implying that dirt and debris may be getting into the system downstream of my air filter. I've looked, but haven't found anywhere that appears to be leaking.

    Have any of you had similar issues you resolved, or do you know of any common failures points on the air intake system I can target?

    Thanks!


    1.jpg
     
  2. OneofFew

    OneofFew Member

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    They assume the silicone is from unfiltered air entering the system. This may not be the case. Silicone can get in through filters, come from filters themselves or come from silicone sealants and anti-seize lube. I would replace the air filter if it is at all questionable. check your maf screen for dirt and debris. Of course check for intake leaks and vacuum leaks.
     
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  3. OneofFew

    OneofFew Member

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    Also I see your silicone levels were on the rise, but then dropped. What changed?
     
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  4. clandr1

    clandr1 Full Access Member

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    Good call out. I put an AC Delco filter in a couple years back, perhaps it's time for a new one.

    The lead content (to me) seems to be the obvious culprit. It seems to correlate with the rise/fall of silicon. I had low oil pressure in December 2017 to the point where I could hear tapping/knocking. I quickly resolved it (oil tube pickup o-ring needed to be replaced) and was happy to see my lead levels had decreased at the next oil analysis/oil change interval. Maybe the additional lead content was causing abrasion with silicon o-rings and gaskets?
     
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  5. OneofFew

    OneofFew Member

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    The faulty o ring itself may have been the source for some of the silicone. I would change your air filter like you said and wait for the next oil analysis to re-assess.
     
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  6. CountryBoy19

    CountryBoy19 Full Access Member

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    Could certain motor oils have silicon in them from the beginning?
     
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  7. clandr1

    clandr1 Full Access Member

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    You know, I hadn't thought of that. A quick Google search found this page:

    http://www.pqiamerica.com/March2013PCMO/mobil1.htm

    If I'm reading the chart right, Mobil 1 has 8ppm of silicon content. If you deduce that from my oil's reading, I'm well within range. Let me know if I'm misunderstanding the chart at the link.
     
  8. OneofFew

    OneofFew Member

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    It don't work like that. the inherent substances in the fresh oil are calculated in.
     
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  9. Matahoe

    Matahoe Full Access Member

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    Blackstone told me that high levels of silicon is from an internal coolant leak mixing with the oil. Perhaps at some point someone put silicate coolant in the radiator and it's mixed in with whatever you have in there now. Either that or you go Baha racing and suckin in that sand??
     
  10. iamdub

    iamdub Content may not be suitable for all audiences

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    Most OEM crank and rod bearings contain a layer of aluminum and silicone. Let's hope the silicone they found was from other sources.
     

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