Creeping and Thickening

[camrydriver111]

I did another oil change where I used 2L of leftover oil from a 5L jug.

I do a yearly OCI so while the leftover jug was in storage oil has been creeping out of the bottle while the bottle is sitting completely upright. I checked the cap for tightness a few times over the course of the year.

When I was pouring in the left-over oil into the engine I noticed the oil was THICKER than the oil coming out of a brand new jug that I opened the same day!

What is happening to my motor oil?

Do you think the viscosity modifiers are creeping out of the bottle, and the oil is becoming more like a straight weight?

Do you think it's air pressure changes due to temperature and weather are forcing the oil out?

Are certain components of the motor oil attracted to the walls of the plastic bottle, causing the oil to creep out of the bottle? Like is attracted to like. Both oil and the plastic bottle are made out of hydrocarbons.

Is this the phenomenon Dr. Haas described in the Motor Oil University?

Quote:
Motor oil becomes permanently thicker with exposure to northerly winter type weather. This is more of a problem to mineral based oils. Waxes form. This is why it is a bad idea to even store a bottle of oil in a cold garage. It goes bad on the garage shelf just because it is exposed to the cold.


It sounds like he is describing reversible separation of oil components. However, could he be describing the creeping and thickening phenomenon I observed?

 

[Shannow]

Originally Posted By: camrydriver111
Is this the phenomenon Dr. Haas described in the Motor Oil University?

Quote:
Motor oil becomes permanently thicker with exposure to northerly winter type weather. This is more of a problem to mineral based oils. Waxes form. This is why it is a bad idea to even store a bottle of oil in a cold garage. It goes bad on the garage shelf just because it is exposed to the cold.


It sounds like he is describing reversible separation of oil components. However, could he be describing the creeping and thickening phenomenon I observed?


The oil "gels" at very low temperatures, even above the "W" rating of the oil, which can be bad.

You can get it back by warming the oil back up to 90C.

http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4008438/Re:_low-temperature_oil_gellin

Another error in 101.

 

[Ducked]

Whaddya mean "creeping"?

Either it leaked, or it evaporated. I'd guess you'd see leakage, though I suppose it depends what its sitting on.

Assuming leakage would be visible, it either evaporated (which happens, but not much, even for super-skinny oils- is this a super-skinny oil?) or...er...it didn't.

I THINK waxing is usually reversible. Oxidative polymerisation wouldn't be, but'll be very, very slow.

There was an article linked to recently which mentioned variation in viscosity measured for different bottles of the same oil, so if your observation has any basis in fact (apart from different ambient temperatures) that might be it.

EDIT: Didn't see the above before I posted. Getting it back at 90C implies its not reversible at normal ambient temperatures, so I'm wrong about that. ENDEDIT.

 

[Kestas]

I think the oil "creeping" on the outside of the bottle is from oil at the mouth from the first pour. Kind of like your maple syrup bottle.

 

[Popsy]

+1
I noticed my jugs always leaks a bit because of that. maybe because of the die hard habit of shaking them before pouring the oil...

 

[BrocLuno]

Hey, as long as it actually pours, it's good. It's oil. As soon as the motor gets at it, it'll be flung everywhere (internally) and heated to op temp. Thin right out

Oil is stored in unheated warehouses all over (case lots) including Canada. Gets mighty cold for weeks on end, never is a problem. You'd never know what temps your oil has been exposed to before purchase, and it still works just fine

Oil U is way off base here, basically fear mongering to up-sell synthetics. Whether this is because of the author owning big shares of synthetic producer (?), or just some personal bias, it's patently wrong. Oil does not change chemistry at human scale temp swings.