High silicon content in oil

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clandr1

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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
 

OneofFew

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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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clandr1

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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.

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

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

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?
 

OneofFew

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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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clandr1

clandr1

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OneofFew

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

Matahoe

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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 Baja racing and suckin in that sand??
 
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iamdub

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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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