Higher viscosity & higher wear?

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Another 4k run on Scion XB. This one was a 5w40 CarQuest Euro oil apparently. Viscocity stayed in the 5w40 range, but even though my driving conditions remained the same - I see a bit more Iron in this sample than I had with Castrol Magnatec 0w20. Usually higher viscosity brings the wear numbers down, but here I see the opposite... Opinions? Here is the Magnatec UOA.
 
Considering we're talking ppm and only have one sample from each I'd say it's hard to make any kind of determination. There are far too many things to factor in with only one sample of each. Looking at the dates it might be accurate to assume one run of the oil was from summer to fall, and the other run from fall to winter, when temperatures play into it, negatively. I'm interested in our resident experts comments. I'm also assuming there was a typo in the miles [8,000] in the 11/23 report?
 
It was a typo by Blackstone. Same exact engine at 80k miles (NOT 8K miles) and at 84k miles. Why Blackstone did not combine the two samples into one - I do not know. I guess they assumed that it is two different vehicles due to the typo in the first UOA. But it is one vehicle, one engine, first sample at 80k and second sample at 84k miles. Castrol was run in the Summer and CarQuest Euro (Wolf's Head oil with a different label) was run in the winter. Should've been the other way around, I know. But past is past. But could just the temperatures affect the wear so much? I live in Charlotte and it almost never got below 20 degrees at the coldest. Hit 10 a couple times, but just intermittently.
 
Temperature can have an impact, but again we are talking ppm 2 iron vs. 17? I'd say that's nothing, you'd need at least 2 oci's worth of data from each oil to even begin to make some kind of call. Even that might be a stretch. The other items on the report are too close to call.
 
February versus November? Yeah, that's not going to help. Also, comparing different oils is generally an exercise in futility, it isn't the purpose of Used Oil Analysis and the tool isn't precise enough to allow such small variations to be a guide.
 
You drove 78K from Nov 16 to Feb 17? Is that right? OK, I see the typo, but I have use 0-20 for several years now and I am convinced that 20 wt oils do not increase engine wear in engines designed for 20 wt oils.
 
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Originally Posted By: Rolla07
Comparing a new report to old doesnt help...8k miles on engine vs 84k miles makes a difference..


Your right, an engine with 84K should wear LESS. Having said that this is a typo unless the OP drives a lot.
 
Originally Posted By: Vlad_the_Russian
I see a bit more Iron in this sample than I had with Castrol Magnatec 0w20. Usually higher viscosity brings the wear numbers down, but here I see the opposite... Opinions?

I think you are trying to read too much into this. As was stated earlier, a $25 UOA is not a good tool to compare one oil against another, unfortunately.

Both are great UOAs as far as I'm concerned.

With that said, I don't think you're gaining anything by running Xw-40 oil in your Scion. If the owner's manual calls for Xw-20, then that's what I'd probably stick with.
 
If a 20wt keeps the parts separated there will not be any improvement using a 40wt keeping parts more separated. The oil held up well in both uoas. The Magnetec seems the best oil for your operation of the vehicle.
 
Originally Posted By: Oregoonian
Any reason that your only doing 4K ????
too modern to do 3k, but too stubborn to reach 5k or more. And just like short OCIs, since I need to go through my oil stash quicker.
 
I am really leaning towards 20wts all of sudden... Once I burn through my stash of 0w40s, and 5w30s - there should be enough data for the new Mobil oils such as 0w20 HM and 0w20 Annual oil. I'd go with Magnatec 0w20, but it is not available anywhere cheaply anymore...
 
Originally Posted By: demarpaint
Considering we're talking ppm and only have one sample from each I'd say it's hard to make any kind of determination. There are far too many things to factor in with only one sample of each. Looking at the dates it might be accurate to assume one run of the oil was from summer to fall, and the other run from fall to winter, when temperatures play into it, negatively. I'm interested in our resident experts comments. I'm also assuming there was a typo in the miles [8,000] in the 11/23 report?

It does, I believe.
This is what they call 'cold start wear' ...... a form of corrosion wear.
No, it's not an adhesion wear, neither is it a an abrasion wear.

Originally Posted By: aquariuscsm
I'm guessing it's because Castrol is a better oil.

I would agree so ....with 'stouter' additive package in the 'better' oil.
Marketing adverts would have us believe that xW20 provides lower cold start wear .......
giving me the impression that it's lower viscosity that lowers cold start wear ....
and this cold start wear is adhesion wear or abrasion wear in nature.....
not elaborating that this cold start wear is corrosion wear..
Nothing was attributed to stronger additive package, hence the confusion.
JMHO.
 
Originally Posted By: Vlad_the_Russian
Usually higher viscosity brings the wear numbers down...


That's what one would expect, but I don't recall seeing much evidence of it.
 
Originally Posted By: Ducked
Originally Posted By: Vlad_the_Russian
Usually higher viscosity brings the wear numbers down...


That's what one would expect, but I don't recall seeing much evidence of it.


Here is the latest one I could find. In the very first sample oil's viscosity was the lowest from all samples, and the wear numbers were higher. But as the owner switched to a more viscous oil - wear numbers went down. It's just one out of many that I've seen with such trend. All here on BITOG. Just surprised that my engine went against the logical trend that many other engines experience...
 
Originally Posted By: Vlad_the_Russian
I am really leaning towards 20wts all of sudden... Once I burn through my stash of 0w40s, and 5w30s - there should be enough data for the new Mobil oils such as 0w20 HM and 0w20 Annual oil. I'd go with Magnatec 0w20, but it is not available anywhere cheaply anymore...


Walmart bro!
 
None of 5 walmarts around me carry Magnatec 0w20, and Edge 0w20 doesn't have the magical "clinging" thingies that magnatec advertises, which I believe to be the reason for the low wear numbers.
 
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