Blotter test for WVO contamination of engine oil ???

[JOAT]

I've started trying the old school "blotter test" to see if there are any early signs of WVO induced oil degradation, contamination, or polymerization that could be detected at home. Since I have a bypass filter I may not be the best one to be doing this, but it's easy if anyone else wants to try it.

Basically, you just take a few drops of hot oil from the dipstick and place them on high quality paper. Suspend it level so the bottom isn't touching. Fine filter paper or non-glossy business cards work fine, tho lab filter paper or chromatography paper is best. Cheaper papers can cause uneven soaking or spotting, but still give some indications.

After the oil has soaked into the paper as best as it will (could take some time), you look at the stain for signs of ageing or contamination. It is somewhat art and not entirely trustworthy, but gives you some idea of oil condition.

-a light colored stain, evenly spread indicates good oil
-a medium to dark stain, evenly spread indicates aging oil (and soot buildup in diesels)
-a fairly evenly spreading but darker spot in center occurs normally as oil ages and oxidizes, and also indicates the oil dispersants are losing effectiveness.
-a very dark spot in the center, especially if shiny or won't soak in, is a sign of sludge buildup or very contaminated oil. Often seen in short drive vehicles.
-streaks radiating out or clear spots indicate contaminants like antifreeze.
-little dots usually are abnormal too, but I've never seen this myself.

It would be interesting if someone with known heavily WVO contaminated oil could try this and see if there are any really distinguishing signs.

For even more advanced analysis, you can set one end of the paper in a solvent and as the solvent soaks accross it separates the sample further. Something we did in HS chemistry but I don't have any specifics as it relates to motor oil