? for oil analysis experts

Maybe soot?

 

This is oil that is too thick. I suspect some blends have chemicals added to prevent oil from being too thick so it flows properly. These chemicals are probably worn down.

 

Just out of curiosity, how long would oil have to remain in the crankcase before those chemicals wore down?

 

If it's just one sample ignore it. Drain the oil then re sample @ 10-12k. Labs can and do screw up a sample at times.

 

Spot is usually the culprit unless someone put that lucas garbage in the oil.

 

You'll get nothing but guesses without more information. What does the rest of the same look like? How much did viscosity raise? How old is the oil? Soot, oxidation, nitration and several other things could cause a viscosity increase, most of which will show on the oil sample as elevated as well.

 

Heat can cause thickening. Are the oxidation levels high as well? What oil and what is the tested viscosity? Does this engine run hot and or work hard?

 

I would love to know more about oil sampling. We send ours away. This is an area I don't know too much about, so I really can't comment on how long chemicals last and what not. Too many variables to factor in as well.