0W20 PP, 5W30 PUP 50/50 mix

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Pennzoil Platinum 0W-20 SN Plus 50%, Pennzoil Ultra Platinum 5W-30 SN 50%

This is fairly well what I run in a 2017 3.6L Pentastar Grand Cherokee (even though it calls for 0W-20) and a 2018 5.0L Coyote F150 (calls for 5W-20). Just wanted to confirm my belief that I could not end up with a 10W or more by mixing. (It would have to be some weird chemistry to do that.) I thought I would end up with a very light 30 grade @100°C and sure enough I did. Didn't expect it to be closer to 5W however, but it looks like it is.

0w20 5w30 VOA.jpg


0w20 5w30 graph.jpg
 

doyall

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Because of all the protestations from some "learned" forum members to the effect that you cannot be sure what W grade will result when mixing oils and those "learned" forum members declination to answer my specific question as to whether mixing a 0W and a 5W can yield something greater than a 5W.

You have obviously been around for a while so you should have seen some of the many threads where those protestations have been made.
 
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So how did you determine that your mixture was closer to a 5W by analysis ?
 

doyall

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So how did you determine that your mixture was closer to a 5W by analysis ?
With visc at 40°C and 100°C from analysis, the curve can be plotted. The graph fairly well suggests 5W, no?

...
PP 5w30 is really thin for a 30, you could just go straight to that
At 9.8 [email protected]°C, PP 5W30 SN Plus, when combined with moderate fuel dilution, is certainly a viable option.

May just try to find a 0W low-visc 30 non-European formula oil.
 

doyall

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Unless you test the low-temperature cranking viscosity (−30°C), you'll never know ;)
I suppose you don't get -30° often, so will the 0/5W part ever matter?

Based on the graphs of the costituents and the whole, I think it is safe and logical to conclude it is no longer a 0W, therefore it has to be a 5W (as there is no such thing as 3.75W) unless someone is willing to suggest it could be a 10W. Where are all the "learned" forum members here.

Thank goodness it doesn't get cold enough here for it to be problematic.
 
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Well as you already know, "learned" members (as I'm not one of them I'll use subjonctive here) could tell you that you may have affected the delicate balance of pour point depressants or improvers (I forgot how they are called and don't feel like looking for it) so the cold rating could be dramatically affected.

Other could also tell you that by mixing two oils you may have upsetted the anti-foaming agents and ended up with an oil that will foam like Dawn in a dishwasher and destroy your engine. Forum possibilities are endless :D
Now where's my popcorn?

(in case that wasn't clear, this is a humoristic post)
 
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Based on the graphs of the costituents and the whole, I think it is safe and logical to conclude it is no longer a 0W, therefore it has to be a 5W (as there is no such thing as 3.75W) unless someone is willing to suggest it could be a 10W. Where are all the "learned" forum members here.

Thank goodness it doesn't get cold enough here for it to be problematic.
None of which (as far as I know) have the ability to run the suite of tests in SAE J300 to determine the cold-cranking and pumpability characteristics of an oil.

Popsy knows what he is talking about.
 
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