Thin to thick oil converts?

[wemay]

 

[zeng]

Originally Posted By: Shannow
Originally Posted By: Doug Hillary
People may forget that 20W-50 was a specific lubricant viscosity developed by Duckhams (Q20-50) in 1958-9 to compensate for the poor technical attributes of the BMC Mini. It became the do-all lubricant for many !


Good to see you posting more Doug...

Similarly in these dscussions, I'm paitned as a thick advocate...the L67 in my Caprice is 20W50 as per the manual, but gets 5W30/10W30 A3/B4, my Nissan Navara was specced 15W40, got 5W30 A3/B4, the Captiva is specced 5W40, gets 5W30 Dexos2/C3.

Welcome back Doug, but Shannow btw .. I am a thick practitioner .
I'd replaced:
80W90 with SAE 140;
5W30 UTTO with SAE 140;
15W40 with 20W50 depending on circumstances;
AW46 with AW68, at times mix AW100;
.... and selected xW40 in Mitsubishi's calling for xW30 to xW50 and in Kia's and Yota's calling for xW30 to xW40.
There is such a thing as pay less for 'more' in oil grade selections though ....
Maybe it's just me.

 

[Saxon1285]

Originally Posted By: oil_film_movies
If you look at a bunch of used oil analysis, you'll see oil many times thickens in normal OCI's.


I hardly saw any case of.
I admit I'm not a used oil analysis fan, but I looked at quite a lot here, and especially on oil-club.ru/.de

I hope you compare the Visc from the used oil analysis with the same oil's visc in VOA ... not with the Visc from the preceding used oil analysis (as many do)...

All I saw was a huge bunch of 40's and sometimes 30's thinning out to a lesser grade.

It's enough to compare the used oil analysis 100C visc with the official SAE J300 visc classification
SAE J300

40's: 100C visc between 12.5--16.3cSt
30's: 9.3--12.5
20's: 6.9--9.3

For some reason, it seems that 20's aparently do better (larger oil sumps? less shear/VII? IDK)

How many used oil analysis show oil going UP a grade?

Let's see the general trend, not the exceptions.