Oil darker on dipstick when measured warm.

[uart]

Ok, this one is not exactly rocket science, the oil as seen on my dipstick is usually darker if the car has been driven moderately (or hard) shortly before checking the stick. If on the other hand I check the oil stone cold, first thing in the morning say, then it always looks relatively pristine.

I assume it's because impurities settle out over night, whereas after a good run the oil has been nicely mixed and the impurities are all in suspension. Like I said, not exactly Earth shattering news. However I was just wondering how much of this is due to the fact that I normally have a shot of MoS in my oil, which is probably what I'm mostly seeing suspended in the warm oil.

So do others also notice this effect, oil on dipstick looks darker when checked warm and much clearer when checked stone cold?

 

[The motor guy]

It all gets mixed together once the engine has been running.

 

[LeakySeals]

What oil brand? Sounds like the oil is not keeping deposits in suspension very well. Settling on engine surface, then churned up again with oil flow. If it helps to compare...I have no real change in the "looks" of the oil on the stick hot or cold. If anything it looks cleaner warm.

Maybe that Mos additive is a cloudy heavy substance?

 

[uart]

OK thanks guys. If others aren't seeing this then I assume it's the MoS (moly disulfide). That's kind of what I suspected it was.

BTW. The MoS is a solid (non soluble) lubricant. Controversial I know, but I had a good experience with it saving my engine a long time ago.

 

[SS1970chrysler]

My cars always do that. Some of the "stuff" in the oil settles down to the lower quarts after it sits awhile. The top quart always looked good, while it was always black when drained.
I did an experiment on this using a '71 dart a long time ago. I had forgotten to dump the oil from the catch pan overnight and used a straw with my finger over top to pull oil from various depths and put it in shot glasses. The darkness changed by inches of depth.

 

[uart]

Originally Posted By: SS1970chrysler
My cars always do that. Some of the "stuff" in the oil settles down to the lower quarts after it sits awhile. The top quart always looked good, while it was always black when drained.
I did an experiment on this using a '71 dart a long time ago. I had forgotten to dump the oil from the catch pan overnight and used a straw with my finger over top to pull oil from various depths and put it in shot glasses. The darkness changed by inches of depth.


Thanks ss1970, that's exactly what I'm seeing too. Like I said, the MoS (which is very dark) is probably settling out somewhat as it sits too.

 

[badtlc]

Mine is the opposite. Cleaner when hot, darker when cold.

 

[KCJeep]

Originally Posted By: badtlc
Mine is the opposite. Cleaner when hot, darker when cold.


Mine too. I presume it is due to the oil film on the dipstick being thinner when it's up to temp. And I use MoS2 as well.

But you can see the gray shading of the Mos2 on the dipstick, even on a brand new OCI.