Experiment: 10W-40 thicker than 15W-40

[LucasDK]

To day i made an interesting test:

I placed 2 small samples of engine oil in the freezer at -18 degrees Celsius imitating winter conditions in Europe. The samples were:

Mobil Multigrade 15W-40 (Mineral oil), API: SH/CD; ACEA: A2/B2

and

Liqui Moly 10W-40 (Mineral oil), API SJ/CG-4, ACEA A3-04/B3-04/E3-96

I wanted to test the temperature influence on viscosity at -18 degrees Celsius.

Of course I did not have fancy measuring equipment, but I was turning the jars up side down in order to watch how fast the oils would flow along the side walls of the jars. All this was done promptly after removing the jars from the freezer to avoid the influence from room temperature.

Result: The 15W-40 was less viscous than the 10W-40. In other words, the 15W-40 would give better start properties during winter conditions. I have no idea why this test had this outcome.

Final comment: It is scary to watch how thick engine oil becomes at -18 degrees Celsius.

Lucas

 

[dparm]

Viscosity isn't a super-accurate predictor of cold pumping ability. You should look at the MRV for that.

 

[PontiacFan]

Lucas, Thanks for doing the test.

 

[ARCOgraphite]

There are a lot of videos on youtube of our favourite oil brands being "casually" tested by the a Russian Car Club in sub-zero temps. IN One a petrocanada "synthetic" 5w-30 did VERY poorly against its own brand dino oil, though in a later viddy a petro canada 0w-30 came on strong. http://www.youtube.com/watch?v=ZBsUOAuCG-c&feature=related

 

[NVJ157G]

-18c?! And I thought minus 6 was cold! No wonder you drink all that Carlsburg out there lol.

 

[Bluestream]

Originally Posted By: ARCOgraphite
There are a lot of videos on youtube of our favourite oil brands being "casually" tested by the a Russian Car Club in sub-zero temps. IN One a petrocanada "synthetic" 5w-30 did VERY poorly against its own brand dino oil, though in a later viddy a petro canada 0w-30 came on strong. http://www.youtube.com/watch?v=ZBsUOAuCG-c&feature=related

I don't trust Russians...

 

[LucasDK]

Additional information:

Right after removing the samples from the freezer and letting them reach room temperature, both samples showed a white deposit on the bottom of the jar. It looked like tiny flakes or flocks and they were clustered on the center of the jar. I left the jars for 1 week but the deposit did not disappear. Now after 1-2 months its completely gone. Does anybody know what is was?

Lucas

 

[Rand]

moisture?

 

[addyguy]

Although this test doesn't mean much, I will say that there are a lot of 15W-40's that I suspect are actually 10W-40's or below. They just use the 15W-40 label b/c that is what everyone knows HD oils to be, 15W-40's.

 

[d00df00d]

Originally Posted By: dparm
Viscosity isn't a super-accurate predictor of cold pumping ability. You should look at the MRV for that.

Bingo.

It's hard to fault the OP for his effort, but the test is not really meaningful.