PU Euro 5w-40 viscosity loss/shear - non fuel

[OVERKILL]

Originally Posted By: Quattro Pete
Originally Posted By: OVERKILL
My point, as noted in the OP, was to discuss viscosity loss as it often gets blamed on shear and/or the wide visc spread, yet we are seeing it here on an oil with a much narrower spread and some searching will show T6 also going out of grade, the accidental AMSOIL example...etc. All of these being 5w-40's and going further out of grade that the 0w-40's usually do

If you say so.

But your OP's subject clearly called out PU 5w-40, and the first sentence of your post noted PU 5w-40 as having tremendous viscosity loss, and all your examples (minus the unintentional Amsoil one) also focused on PU 5w-40. So I interpreted it as you pointing to some inherent issue with PU 5w-40 specifically.

But of course, I am a PU 5w-40 user, so anything I say or do at this point will be perceived as me trying to defend it, so I'll shut up now and let others participate in the discussion.

The reason for the focus on PU 5w-40 was that it was a 5w-40 and currently the "hottest" competition to M1 0w-40 on the board IMHO. Yet it did, in a couple of examples, demonstrate some rather remarkable viscosity loss. This got me thinking about it and since that oil was the one I had found the examples of and I had them handy, I chose it for the subject and title

But I didn't want to keep the thread isolated to just PU Euro 5w-40, which was why I ended the post with:

Quote:
Now of course viscosity loss itself doesn't indicate an issue or that the product did not provide adequate protection and that's not the purpose of this thread, it is more to discuss causes of viscosity loss above and beyond fuel contamination as sometimes even the same model of engine will have very different viscosity loss than another fitted to a different vehicle.


Now that we've identified AMSOIL 5w-40 as also doing this, I would like to extend the discussion to all popular 5w-40's if possible and see if we have some more examples of dramatic viscosity loss (which I qualify as dropped down into the 10's or below) that are similar to the two PU 5w-40 examples I cited, the one that shows some decent fuel ingress, the other which suffered from significant heat soak.

 

[Quattro Pete]

Originally Posted By: OVERKILL
that are similar to the two PU 5w-40 examples I cited, the one that shows some decent fuel ingress, the other which suffered from significant heat soak.

Why even bother looking at those with fuel ingress? Any oil, including M1 0w-40, is going to drop viscosity when exposed to fuel. No oil is exempt from this. It'd be more interesting to look at those examples where fuel was not a factor, but viscosity still dropped notably.

OK, I'll keep quiet now.

 

[OVERKILL]

Originally Posted By: Quattro Pete
Originally Posted By: OVERKILL
that are similar to the two PU 5w-40 examples I cited, the one that shows some decent fuel ingress, the other which suffered from significant heat soak.

Why even bother looking at those with fuel ingress? Any oil, including M1 0w-40, is going to drop viscosity when exposed to fuel. No oil is exempt from this. It'd be more interesting to look at those examples where fuel was not a factor, but viscosity still dropped notably.

OK, I'll keep quiet now.

Because it doesn't seem linear. For example, this thread:
http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3788763/1

M1 0w-40, flash point down from 446 to 375F, a 71 degree drop. Viscosity went from 13.5cSt to 11.1cSt, a 2.4cSt drop.

Compared to this one from the first page:
http://www.bobistheoilguy.com/forums/ubb...VW_#Post3664472

PU 5w-40, flash point down from 420F to 355F, a 65 degree drop. Viscosity went from 13.2cSt to 10.0cSt, a 3.2cSt drop.

Both are showing effects of fuel and the flash point drop shows fuel to be significant. But I believe the 2nd example shows more mechanical viscosity loss (shear) than the first one.

The other issue is that Blackstone's fuel measuring methodology, as I pointed out in that first thread, is horribly inaccurate. There's no way a 71 degree drop in flash point is a "trace" amount of fuel. Particularly not when I had LESS viscosity loss, in a car MUCH harder on oil, and with fuel at 5% as indicated by Toromont.

This was my big issue in that thread, people blaming the viscosity loss on shear while seemingly ignoring the flash point because Blackstone says there is "trace" fuel.

 

[Phishin]

Originally Posted By: Quattro Pete
Originally Posted By: Phishin
The guy running PPE comes running to the rescue!!

Have I stated something inaccurate? Let's discuss.

I was just teasin' Pete. Couldn't help myself. But I think everything has been accounted for. PU 5w40E looks like a decent oil, for sure.

 

[chrisri]

You have linked UOAs of turbo cars which will share oil more than NA engines. Although I understand that's UOAs purpose isn't to monitor engine wear, did you noticed that usually metals are lower with PPE even when viscosity drops to a 30 grade?

 

[OVERKILL]

Originally Posted By: chrisri
You have linked UOAs of turbo cars which will share oil more than NA engines. Although I understand that's UOAs purpose isn't to monitor engine wear, did you noticed that usually metals are lower with PPE even when viscosity drops to a 30 grade?


Since one cannot compare wear between different oils using UOA's, no, I didn't look at that.

Also, there were two turbo cars linked, the VW GTI and the Subaru, the Subaru had far less viscosity loss, I assume due to far less fuel in the oil, as it was consistent with the oils used in that car (as it was also with the GTI, which showed fuel ingress in both UOA's).