03 Civic, ST FS HM 5W20, 3500 mi, 5k after head gasket change

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Dec 23, 2020
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Had the head gasket changed at 158k, now at 163k. I did a UOA at 500 mi and another 1000 after HG. This one is a further 3500 mi. There is a steady decrease in wear metals and silicon, which is kind of interesting to see. Looking at PPM/1000 mi, this is the trend at the 500 mile, 1500 mile, and 5000 mi marks:
Al - 11.61 / 4.89 / 0.85
Ch - 29.01 / 5.87 / 1.14
Fe - 56.09 / 23.46 / 5.97
Si - 81.24 / 49.85 / 11.66

I'm also impressed that the viscosity hardly dropped from virgin -- 8.38 cSt to 8.26 over 3500 mi. You can also see how the additives get depleted with use (mostly Boron). I did a VOA of this oil before it went into the sump, which I'll attach below the UOA:
03 Civic 110121.jpg

ST FS HM 5W20 SP.jpg
 
I never understood elemental analysis WRT formulation additives. Where does the boron go? You can't unboron boron.
Does it turn into an insoluable and get filtered out? Is that what the comments suggest?

Thanks for sharing.

Maybe Mola can chime in.
 
I never understood elemental analysis WRT formulation additives. Where does the boron go? You can't unboron boron.
Does it turn into an insoluable and get filtered out? Is that what the comments suggest?

Thanks for sharing.

Maybe Mola can chime in.
You're Boron me
 
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