Oil analysis

[XY74]

I sent in a sample for a baseline, I'll probably get another after a couple more oil changes.  The OLM was at 15% and about 6000 miles on the oil and 16K on the engine,  Rotella T6 15w40.  Seems like it's OK.  

 

 

[customboss]

11 hours ago, XY74 said:

I sent in a sample for a baseline, I'll probably get another after a couple more oil changes.  The OLM was at 15% and about 6000 miles on the oil and 16K on the engine,  Rotella T6 15w40.  Seems like it's OK.  

 

 

K flux? 

[Black02Silverado]

It’s still breaking in and most seem ok.  The potassium being a little high is interesting. Will need to see another sample to see how it’s trending. 
 

What is Blackstone charging now with TBN. It’s been a long time since I looked at their prices. I have heard they went up. 
 

Maybe try Oil Analizers. 
https://www.amsoil.com/p/oil-analyzers-test-kit-postage-pre-paid-oaippkit/?zo=521390

 

 

Edited December 5, 2025 by Black02Silverado

[customboss]

2 hours ago, customboss said:

K flux? 

That’s coolant or diesel fuel marker. Not heat exchanger internal  welds or flux. Dementia might have me forgetting something but this stuff is muscle memory for me. 
 

If it’s a fuel marker ( K is a refinery trace on renewable diesel fuels) 

Edited December 5, 2025 by customboss

[XY74]

I went back and watched the Motor Oil Geek video about fuel additives on YT.  The high potassium is probably coming from the XPD fuel additive I have been using every other tank.  Interestingly he says in a pinned comment that if you are not doing oil analysis, then use XPD.  If you are, then Power Service is better.  Not sure why that distinction.  At any rate, I will probably try the PS additive when I run out of XPD.  Not sure how I would ever tell the difference anyway.......

 

Is it correct that high pottasium can also be a marker of a coolant leak?

 

The test was $50 with TBN.  I had an empty test bottle rattling around in my toolbox for quite a while, I clearly heard it say "use me" when I was about to change the oil on the truck last month.    I mainly wanted to make sure the oil wasn't totally worn out when GM decided I should change my oil.  

[customboss]

1 hour ago, XY74 said:

 

Is it correct that high pottasium can also be a marker of a coolant leak?

Yes. 
 

Didn’t know XPD could give that level of K. If so your fuels dilution is higher than Bklabs is showing.