Oil thickness on the dipstick

[Idlewild294]

I rarely check my oil when the engine is warm, but today it had me wondering what causes the oil to appear thinner near the top of the dipstick? 2/3 of the level between low and full is very visible with oil while the top 1/3 is very thin and virtually clear. When held at an angle under good lighting, a faint line can be seen that appears to mark the top level of oil. Is it because the oil is warm and running down the dipstick as it's pulled up and out, or is there a more scientific explanation? Thanks in advance.

 

[DONWATERS]

Depends where the dipstick goes, some go in a mostly stagnant area, oil may be dark at the bottom, thin at top, but when you drain the oil the color is fine.

 

[CR94]

Good question! Of course, if one holds the dipstick vertically with handle at the top, the upper portion of oil on it will flow down to make the lower part thicker. However, I see something harder to explain going on, on my present car. Checking the oil level is more difficult than in my previous cars, not only because the dipstick tube has curves, and not only because the synthetic oil remains so clear for the first few thousand miles. It often looks as if the upper part of oil on the dipstick tends to peel off cleanly instead of just slowly flowing down in the usual way. I'm not sure whether that's because the synthetic is less polar (?), or because this dipstick is too smooth, or only my imagination.

 

[Ducked]

Originally Posted by Idlewild294
Is it because the oil is warm and running down the dipstick as it's pulled up and out, or is there a more scientific explanation? Thanks in advance.


Gravity is a myth. The Earth sucks.

 

[Linctex]

Originally Posted by CR94
Of course, if one holds the dipstick vertically with handle at the top, the upper portion of oil on it will flow down to make the lower part thicker. .


I always read my dipstick at horizontal (flat) a second or two after pulling it.

You got to give a little tolerance ..... 1mm oil level change on a dipstick mean nothing at all. Don't obsess.

 

[CR94]

Originally Posted by Linctex
Originally Posted by CR94
Of course, if one holds the dipstick vertically with handle at the top, the upper portion of oil on it will flow down to make the lower part thicker. .


I always read my dipstick at horizontal (flat) a second or two after pulling it. ...
I do that too, which minimizes the normal sagging down effect, but it doesn't prevent the top of the oil seeming to peel clean off the metal immediately.

 

[Ducked]

Originally Posted by CR94
Originally Posted by Linctex
Originally Posted by CR94
Of course, if one holds the dipstick vertically with handle at the top, the upper portion of oil on it will flow down to make the lower part thicker. .


I always read my dipstick at horizontal (flat) a second or two after pulling it. ...
I do that too, which minimizes the normal sagging down effect, but it doesn't prevent the top of the oil seeming to peel clean off the metal immediately.

Originally Posted by CR94
Originally Posted by Linctex
Originally Posted by CR94
Of course, if one holds the dipstick vertically with handle at the top, the upper portion of oil on it will flow down to make the lower part thicker. .


I always read my dipstick at horizontal (flat) a second or two after pulling it. ...
I do that too, which minimizes the normal sagging down effect, but it doesn't prevent the top of the oil seeming to peel clean off the metal immediately.


I've seen it suggested on here that synthetic oil (whatever that is) drains off engine surfaces quicker, though of course I've also seen it denied.

Maybe you should get a bottle of old school stuff and compare.